Poultry Farming Practices PDF

CHAPTER 13 Shutterstock.com/C.Lotongkum Poultry CHAPTER SUMMARY Chicken eggs and meat are produced in many ways, including via cage, barn, free-range, pastured and organic sys...

CHAPTER 13 Shutterstock.com/C.Lotongkum Poultry CHAPTER SUMMARY Chicken eggs and meat are produced in many ways, including via cage, barn, free-range, pastured and organic systems. Chickens can be monitored throughout their growth and development within the egg by using a method called candling. Chicks are then grown in rearing sheds, with extra warmth provided by brooder lamps for the first weeks of their life. Different techniques can be used to improve growth of chicks, such as using various light colours to increase their growth rate. Poultry production has many ethical concerns; for example, cage production doesn’t allow chickens to roam naturally. As a result, free-range chickens are slowly becoming more popular, despite the increased production cost for farmers. Ethical concerns must be weighed with production concerns to ensure the most efficient and successful business for the farmer. How has poultry farming changed over time? How can chickens be produced ethically? Are chickens a sustainable alternative to other farm animals?  354 AG TECH FOCUS 9780170443111 13.1 Introduction Poultry are domesticated birds farmed for meat, eggs or feathers. The term ‘poultry’ includes chickens, ducks, geese, turkeys, pigeons, quails, pheasants, and even ostriches and emus. In Australia, emus, mutton birds and parrots were hunted and trapped by Aboriginal peoples for millennia, customary practices that still occur today. An emu caller, made from hollowed- out wood, attracts the male emu away from his nest. Although emu nests could contain up to 15 eggs, it was normal practice for hunters to leave some eggs, ensuring a sustainable emu population and harvests for future years. The first period of Maori settlement in New Zealand is named after a now-extinct giant bird, the moa. Twelve species of moa inhabited New Zealand, the largest birds reaching 3 metres in height. These giant flightless birds were hunted alongside weka (ground hens) and kakapo (semi-flightless night parrots). Chickens descended from the red junglefowl of India over 7000 years ago, arriving in Australia with the First Fleet in 1788. Over time, poultry became a common fixture in Australian backyards, allowing many families to be self-sufficient in their production of eggs and meat. Chickens are still the most popular poultry species in Australia today, although the nature of egg and meat farming has changed considerably. Australia’s poultry industry has become larger and more specialised. Hatcheries, breeding farms, feed mills, chicken meat growers, egg producers and marketing companies have evolved to concentrate on individual steps in the production, processing and marketing of chicken eggs and meat. Today, the poultry industry consists mainly of large-scale producers located near major towns and cities. 13.2 Functions and anatomy Functions Layer birds Layer birds produce eggs that are sold whole as table eggs or processed into egg products such as egg pulp and liquid eggs. Compared with birds used for meat production, layer birds have much lighter frames. All their energy goes into producing eggs rather than meat carcases, with the average commercial layer bird producing around 350 eggs per year. Layer birds are selected for a number of traits, including: high egg production egg weight shell colour and strength a long laying life. hybrid an organism bred Most layer birds are hybrids, produced from crossing pure breeds selected for these from crossing two different production traits. In Australia, approximately 98% of eggs are produced by ISA Brown, varieties, breeds or sometimes species Hy-Line, Hisex and other layer hybrids. Hybrids inherit the superior egg production traits from both of their parents and also display hybrid vigour, meaning they perform better than the average of their parent breeds and are usually healthy and robust. Commercial layer hybrids 9780170443111 CHAPTER 13 – POULTRY 355 are produced by crossbreeding a number of generations of selectively-bred pure lines. As a CHAPTER 13 result, backyard breeders cannot create new ISA Brown, Hisex or Hy-Line layer birds by simply breeding existing birds. Each hybrid layer is the result of a carefully managed and controlled breeding system owned by specific breeding companies. DID The ‘ISA’ in ISA Brown stands for Institute de Selection Animale, the French YOU company that developed this hybrid layer in 1978. KNOW ISA Browns, Hy-Lines and Hisex laying hens are Shutterstock.com/Ivonne Wierink sex-linked hybrids. The colour of the newly hatched chicks is determined by their sex, with males hatching out yellow and females hatching brown. This makes the hatchery’s job of sexing the layer chicks very easy. Meat birds Just like layers, commercial meat birds are hybrids. Since the late 1990s, fertilised eggs from international poultry genetics companies have been imported into Australia to improve the production, fertility and welfare of meat chickens. The high growth rates and large carcases of meat birds are not due to steroids, growth hormones or genetic modification, but are Figure 13.1 ISA Brown hen solely the result of careful selective breeding. Today’s meat chickens are selected for: high meat yields Shutterstock.com/Mriya Wildlife efficient conversion of feed into weight gain (known as feed conversion efficiency) reproductive fitness and fertility leg and cardiac strength disease resistance. Most Australian meat bird hybrids are produced from crosses between the Cobb and Ross breeds. Both sexes are grown and used for meat production. Purebreds Popular purebreds include Australorps, Leghorns, Light Sussex and Rhode Island Reds. Some of these are dual- Figure 13.2 Thirty-day-old purpose birds, being kept for both meat and egg production. meat bird Purebred chickens are an important source of genes for commercial layer and meat breeders. New crosses are developed from purebreds with desirable characteristics. Poultry clubs and DID Bantam chickens are smaller chicken fanciers play an important role YOU breeds of chickens. Many full sized or standard breeds have in preserving and protecting the genetic KNOW a bantam version. variation of chickens.  356 AG TECH FOCUS 9780170443111 Poultry by-products Poultry by-products include feathers; down; blood, meat and bone residues from processing plants; manures; and soiled bedding or litter from housing. Manures and soiled litter are processed into fertilisers, while other by-products are rendered to produce meat and bone meal, blood meal, fats and oils. Poultry meat meal is an important source of protein in some animal feeds. Fats and oils are used by pharmaceutical and chemical companies. Feathers and down are used for insulation and padding for pillows, doonas, sleeping bags, clothing and furniture. Feathers and down are sourced from ducks and geese, not chickens, and are imported into Australia. Birds are often plucked alive, up to four times a year.The Traceable Down Standard has been introduced to address animal welfare concerns in the feather-and-down industry. To meet the standard, producers have to conform to local animal welfare regulations and cannot engage in live plucking. AG IN FOCUS MUTTON BIRDING IN AUSTRALIA AND NEW ZEALAND Identify Shutterstock.com/ivandon Tasmanian Aboriginal peoples and the Rakuira Maori have harvested mutton bird chicks from the wild for thousands of years. Understand Mutton birds, or short-tailed shearwaters, are valued for their meat, oil, feathers and down. Chicks are harvested in April, just before they get their flight feathers and Figure 13.3 The short-tailed shearwater or mutton bird migrate to the Arctic. They are at their heaviest at this stage, and contain the most gurry, or gut oil. Apart from being a source of food and fibre, mutton bird harvesting is also an important cultural practice. Commercial mutton bird harvesting is only carried out by local Aboriginal and Maori people, and is conducted in a sustainable fashion. Populations of birds are monitored to ensure harvesting will not have long-term Investigate how these birds are impacts on mutton bird colonies. During the harvesting process, burrows are used by Tasmanian Aboriginal peoples and learn how to cook protected because birds will reuse these over a number of seasons. mutton bird. Unfortunately, mutton bird populations are threatened by environmental changes and commercial fishing. Animal rights activists are opposed to the harvest of the chicks, which they view as inhumane. Discussion 1 Why is harvesting conducted just before the chicks migrate? Read about the steps in harvesting and processing of 2 Identify some uses of, and products made from, mutton birds. mutton birds in New Zealand. 3 Explain why mutton birding is under threat. 4 Discuss the practices used to manage and harvest mutton birds sustainably. 9780170443111 CHAPTER 13 – POULTRY 357 Anatomy CHAPTER 13 Poultry terms Newly hatched chickens are called chicks. Up until one year of age, males are called cockerels, after which they are known as roosters or cock birds. Until they start laying eggs, females are known as pullets. Once they start laying they are called hens. Anatomy of a rooster and hen Points Sickle feathers Comb Nostril Upper beak Tail Face Comb WS Earlobe Nostril Tail Saddle Face Cushion Homework Back Earlobe Review what you know about Lower beak poultry anatomy by completing Back the worksheet on NelsonNet. Wattles Hackle feathers Breast Hock Fluff Spur Shank Hock Toes or claws Figure 13.4 Anatomy of a rooster and hen Shutterstock.com/logika600 Eggshell Chalaza Structures of an egg Exterior albumen Eggs consist of a hard protective shell with thousands Shell membranes Middle albumen of tiny pores to allow airflow. The central yolk has a Germinal disk tiny germinal disc where the chicken embryo will Chalaza Egg yolk develop if the egg is fertilised. The yolk provides food Air cell for the developing chick and is held in place by the chalazae. The egg white, or albumen, cushions the Figure 13.5 The structures of an egg yolk and acts as a barrier against external germs. WHAT IS INSIDE AN EGG? PURPOSE METHOD To examine the structures inside an egg 1 Carefully crack an egg onto a paper plate and identify the structures RISK ASSESSMENT shown above. LET’S ENGAGE Wash hands before and after DISCUSSION this activity. 1 Draw a labelled diagram of your egg. MATERIALS 2 Construct a table detailing the Fresh eggs structures and functions of an egg. Paper plates Probes or icypole sticks  358 AG TECH FOCUS 9780170443111 LET’S REVIEW LOOKING BACK 1 Identify the two main types of poultry enterprises. 2 Define the following terms: hen, pullet, chick, rooster, meat bird, layer, dual-purpose bird and hybrid. 3 How can you tell male and female layer hybrid chicks apart? 4 Why are sex-linked hybrids considered better than purebreds for commercial production? 5 Identify five products made from chickens or other poultry species. FOR YOU TO DO 1 Examine a hen or rooster and identify the main anatomical features. 2 Compare layer birds and meat birds in terms of the traits used for selective breeding. 3 Contact your local poultry club or visit a poultry fancier to learn about the range of purebreds in your area. TAKING IT FURTHER 1 Write a report on one breed of chicken, outlining its appearance, history and uses. 2 Eiderdown is considered a sustainable alternative to other types of down. Investigate Watch a video about the the eiderdown production process and discover why eiderdown is so highly regarded, eiderdown production process and why it is much more expensive than other down. 13.3 Production Cycle Layer production cycle Breeding farm Roosters and hens housed Culled together to produce fertile eggs Fertile eggs Hatchery Male chicks Eggs placed in incubator Sexing, vaccination, Hatching: +/- beak Setting: 18 days 3 days trimming One-day-old female chicks Rearing shed Brooder lamps used for first five weeks 16-week-old pullets Layer housing Cage Barn Free range Pastured Figure 13.6 The production cycle of layer birds 9780170443111 CHAPTER 13 – POULTRY 359 The hatchery CHAPTER 13 Hatcheries are specialised facilities for incubating eggs. Fertile eggs from breeding farms are placed in an incubator for 21 days. The temperature, relative humidity and airflow are controlled to provide optimum conditions for the developing chicks. Incubation is divided into two periods. 1 Setting: during the first 18 days, the eggs are turned throughout the day to stop the developing chick from sticking to the shell. 2 Hatching: for the last three days, the eggs are not turned so the chick has time to prepare for incubator a device used hatching. to optimise conditions for hatching fertile eggs After hatching, birds are sexed. Male chicks are separated and culled because DID Newly hatched chicks absorb the they cannot lay eggs. The females are YOU remains of their yolk and use this as food for up to 72 hours after then vaccinated. Sometimes the chicks’ KNOW hatching. They do not need food beaks are trimmed to reduce injury and during this stage. cannibalism. Learn more about the egg production cycle at Australian Eggs. AG IN FOCUS MALE CHICKS AND GENE MARKERS Identify A number of new technologies are currently being developed to sex chicks while they are still in the egg. Understand The CSIRO is investigating using gene markers to separate male chicks from females before they hatch. A gene marker is a segment of DNA for which the location is known and associated with a particular gene. The marker might be part of the gene or close to it. If the presence of the marker is detected, it means the gene is also present. Eggs can be scanned at the hatchery for the presence of a sex-related gene marker at nine days incubation. Male eggs can be identified and disposed of humanely, reducing the costs associated with incubating, handling, sexing and disposing of male chicks. Alternatively, the male eggs can be used by pharmaceutical companies to produce vaccines. Eggs injected with viruses at 11–12 days’ incubation are used to grow and multiply virus particles that are then processed into vaccines. Influenza vaccines are routinely grown in fertilised eggs. Discussion 1 What is a gene marker and how can it help reduce the number of day-old chicks that must be disposed of? 2 Research how male layer eggs can be used in vaccine production. 3 Brainstorm as a class other potential solutions to reduce the number of male chicks being culled. Prepare a report describing one of those ideas in more detail. Vaccine production with eggs  360 AG TECH FOCUS 9780170443111 Rearing sheds brooder a heating device Day-old females are transported to rearing sheds. The chicks are placed under brooder lamps used to simulate conditions for the first five weeks to keep them warm. After this age, they are able to regulate their body under a sitting hen temperature. Layer housing At 16-18 weeks, the chicks (now called pullets) are transferred to layer housing. Within a few clutch the number of eggs weeks they will start laying eggs. Usually a hen will lay one egg per day for three to eight days laid on consecutive days then have a break. The number of eggs a hen lays in a row is called a clutch. Culling moult the loss and After approximately ten months, the layers will moult, signalling the end of the first laying replacement of a chicken’s season. Their feathers will fall out and be replaced. Laying will cease during this period. Hens feathers, usually associated with shortening of day length; are sometimes culled at their first moult when they stop laying eggs. They can be kept for a egg production ceases until second laying season but usually produce 10–30% fewer eggs. moulting has finished Meat production cycle Meat chickens are also hatched in Shutterstock.com/branislavpudar incubators at a hatchery but are not sexed because both males and females are grown for meat. After vaccination, they are transported to growing farms where they are placed under brooder lamps. Meat chickens have been selectively bred to grow much faster than layer birds so, within 30 days, some will have already reached their target weights for processing. Ideal carcase weights depend on Figure 13.7 Meat chicks at the hatchery what the chicken is to be used for. Birds used for the production of fillets, for example, are usually left to grow larger and are processed as late as 65 days. Some of the chickens are harvested at any one time in a process called ‘thinning out’. Up to five batches of chickens will be harvested this way from each shed. After the last chickens have been harvested, the shed is cleaned and prepared for the next batch of meat chickens. Hatchery Fertile All day-old eggs Eggs placed in incubator Vaccination, chicks males and Hatching: Setting: 18 days females kept 3 days Breeding farm Growing farms Roosters and hens Barn housed together to produce fertile eggs Free range Figure 13.8 The production cycle of meat birds 9780170443111 CHAPTER 13 – POULTRY 361 INCUBATING AND CANDLING EGGS CHAPTER 13 PURPOSE To monitor the development of eggs in an incubator. © JP Ventures LLC & Incubator Warehouse. LET’S ENGAGE Day 3 Day 6 Day 8 Day 10 Day 15 Day 19 Figure 13.9 Egg candling highlights the development of a chick inside the egg. days. Place the egg over a small RISK ASSESSMENT hole in a cardboard box and use a smartphone flashlight to illuminate Incubators can harbour germs the egg from outside the box. The egg that may cause disease in can be viewed through an eye-hole humans. Make sure to wash cut into the top of the box. your hands before and after 4 During the last three days, increase handling eggs. the humidity by placing a pan of extra water on the floor of the MATERIALS incubator. Remove any turning Fresh, fertile eggs devices at this time. Incubator 5 At 21 days, place hatched chicks in a DS Candling equipment OR smartphone brooder with food and water. and cardboard box Data scenario Homework DISCUSSION Investigate the relationship METHOD 1 Make sketches of the changes between Egg size and hatchability by completing the 1 Use fresh (less than one week old), in the eggs during development. data scenario on NelsonNet. clean, fertile eggs that have been Compare your sketches with the turned daily before incubation. video, ‘Development of a chick’. 2 Set up the incubator according to the 2 Did all the eggs develop? During manufacturer’s instructions. candling, what changes did you 3 Candle eggs before placing in notice to the eggs that didn’t Development of a chick incubator, then every two to three develop?  362 AG TECH FOCUS 9780170443111 Systems Most poultry enterprises are intensive, meaning animals are kept at high stocking rates in relatively small areas. Layer systems Cage production Conventional cage production involves groups of between four and 20 hens housed in stacked cages inside large sheds, each containing up to 100 000 birds. Each bird must have a minimum of 550 cm2 of floorspace (roughly the size of this book). Feed and water are delivered automatically and eggs roll along the sloping floor to collection trays at the front of the cage, keeping them clean and free from damage. Manure is collected and moved along on conveyer belts to avoid soiling the cages below. Consumer concerns about animal welfare have reduced the popularity of this production system. Although hens housed in cages are unable to express some of their natural instincts and behaviours, they have lower rates Shutterstock.com/TTstudio of mortality and cannibalism than other production systems. Hens housed in cages are also safe from potential predators. Furnished cages are a new, more bird-friendly version of cage production. These cages are fitted out with perches, nesting boxes and areas for dust bathing. Barn production Figure 13.10 Cage egg production Barn production involves up to 30 000 birds being kept indoors in large sheds. Each bird is required to have a minimum of 800 cm2 of floorspace. Birds are free to roam around the shed litter poultry bedding and have access to nesting boxes in which to lay their eggs. Flooring is composed of litter, wire material, often composed of mesh or slats. Some barns also have perches. sawdust, rice hulls or straw Barn production is more expensive than cage systems, and eggs must generally be washed due to soiling. Birds are also more likely to die or suffer from injuries due to cannibalism. They are, however, safe from predators. Free-range production In free-range production, hens Alamy Stock Photo/Adrian Sherratt are kept in sheds similar to those used in barn production but given free access to outdoors during daylight hours. According to the Watch free range chickens in 2018 Australian definition of free- real time with the Sunny Queen Chooktracker. range production, stocking rates must not exceed 10 000 birds per hectare (equivalent to each bird having 10 000 cm2 of floorspace). This is high compared with international standards, where free-range systems are often Figure 13.11 Free-range egg production limited to below 2500 birds per hectare. 9780170443111 CHAPTER 13 – POULTRY 363 Free-range systems are more expensive than cage or barn production, and eggs must be CHAPTER 13 washed due to soiling. Birds also suffer higher rates of mortality and cannibalism, and may be prone to attack from predators. Pastured production In pastured production, hens are Shutterstock.com/TFoxFoto housed in purpose-built trailers or caravans and have free access to the outdoors. Stocking rates are much lower than other systems, and birds are regularly moved to Watch the Landline epsiode new pastures. Just like free-range about pastured egg production. hens, pastured hens are able to express a full range of natural behaviours. However, this is an expensive production system and can be associated with higher rates of cannibalism and mortality. Figure 13.12 Pastured egg production with a maremma dog Predators are also a problem. keeping guard Electric netting is used to keep hens in and predators out, and maremma dogs are often kept as guardians to protect the flock. DID Maremmas are used as WS Meat bird systems YOU guardian dogs for chickens, Homework KNOW lambs, goat kids and even Camden Park Poultry farm fairy penguins! Barn production grows meat chickens for a large processing company. Investigate Meat birds can be housed in large their business by completing Alamy Stock Photo/FLPA the NelsonNet worksheet. sheds, similar to those used for barn production of layer birds. Up to a dozen or more sheds may be present on the one farm, with each shed measuring 150 metres or more in length. Meat bird stocking rates are calculated per kilogram of bird, which means that more young meat birds can be housed in a DS given space than older, larger Figure 13.13 Barn production of meat birds Data scenario birds. Thinning out the flock as Homework Explore how male and they grow means that producers can avoid exceeding maximum stocking rates as the birds get female meat chicks grow by bigger. Depending on the type of shed, meat birds can be stocked at a rate up to 40 kg/m2. investigating the data scenario Meat bird growth rates on NelsonNet. Free-range production Birds are allowed access to the outdoors through ‘pop holes’ as soon as they are old enough to withstand outside temperatures. Free-range producers generally stock their barns at a lower rate than for barn production to compensate for the increased difficulty in controlling climate in these open barns. Lower stocking rates also allow the birds to move around and find pop holes more easily. Certified organic Organic meat chickens must only receive certified organic feed. They also must not receive vaccinations (unless legally required) or certain medications, including antibiotics. Certified organic meat chickens can be raised in barn or free-range conditions. 364 AG TECH FOCUS 9780170443111 RSPCA-approved meat systems Birds must be housed at a lower stocking density and must have access to perches and other enrichment objects, such as things to peck. Producers must also use approved lighting regimes and bedding materials. LET’S REVIEW LOOKING BACK 1 Define the following terms: brooder, incubator, clutch, moulting, thinning out and litter. 2 Describe three systems of layer and meat production. 3 Why would free-range, barn and pastured eggs require washing, but not cage eggs? 4 Outline how layer and meat bird stocking densities are calculated. 5 Why are meat birds thinned out rather than harvested all at the same time? FOR YOU TO DO 1 Construct a table to compare the following features of cage, barn, free range and pastured egg production systems: minimum space per bird, cost of production, washing eggs due to soiling, mortality (death) rates, cannibalism rates, exposure to predators and ability to express natural behaviours. 2 Analyse the benefits of keeping laying hens for a second season, compared with culling after moulting and breeding replacement layers. 3 Investigate the types of eggs available at the supermarket. For each type, make a record of: brand, price, production system and stocking density (for free-range and pastured eggs). 4 a Survey parents and teachers regarding their knowledge and attitude towards barn, free-range and organic chicken meat production. Questions could relate to which type of chicken they eat, animal welfare and the cost of chicken meat. b Conduct the same survey with your peers. c Compare your results. How did age affect your results? TAKING IT FURTHER 1 Visit the Australian Eggs website to find out more about different production systems. Australian Eggs 2 Investigate turkey farming in New Zealand. 3 What other birds are farmed in Australia? Research this question, choose a bird and describe the production system. Make sure to include a flowchart detailing the system in your answer. Turkey farming 13.4 Management Environmental management Distribution of poultry farms Poultry farms have traditionally been located near major towns or cities to reduce the cost of transport to markets and allow access to services such as electricity. As cities have grown, increasing land values and environmental complaints about noise and pollution have put 9780170443111 CHAPTER 13 – POULTRY 365 poultry farms under pressure. More farms are now being set up in regional areas close to grain CHAPTER 13 growers, to reduce the cost of feed. Climate Temperature, airflow, humidity and air quality need to be monitored and controlled. These factors can vary over short distances so it is important that the microclimate around the birds is measured and assessed. How climate is managed depends on the stage of production. During incubation, microclimate the climate temperature is kept at 37.4–37.6°C but relative humidity is increased during the hatching period. in a very small area, which can vary greatly from This helps to avoid chicks sticking to shells as they hatch. Similar conditions can be created in a the overall climate of a small incubator by placing a pan of water in the base during the last three days. larger area During brooding, the temperature needs to be gradually reduced over the first five weeks. This can be achieved by raising brooder lights higher each week. In large sheds, brooder guards WS are used to keep the chicks near lights. The guards are then gradually moved further out to Homework allow chicks access to more of the shed. Learn more about temperature Chick behaviour can be used to assess brooder temperature. Chicks will huddle together requirements for chicks by under heat lamps if too cold, and pant and spread their wings when too hot. completing the worksheet Brooder temperatures for chickens and turkeys on NelsonNet. Temperature too high Temperature correct Chicks are silent. Chicks are evenly spread. Chicks pant and wings droop. Chirping indicates contentment. Chicks move away from brooder. Temperature too low Draught Chicks crowd around brooder. Brooder requires investigation. Chicks loud and distressed. The brooder may be influenced by uneven flow of air, light or external noises. Figure 13.14 Temperature-related brooder behaviours Layer and meat chicken housing is ventilated to keep temperatures between 20–24°C. At cooler temperatures, birds will start using food energy to keep themselves warm. At higher temperatures, birds have lower weight gain, poorer shell quality and lighter egg weights. Foggers, fans and sprinklers can be used to keep temperatures down in hot weather. Ventilation also reduces the build-up of dangerous gases such as ammonia, carbon dioxide and sulphur dioxide. Some gases are denser than air and sink to the ground. In shed situations, this can lead to dangerous conditions at bird height. 366 AG TECH FOCUS 9780170443111 Naturally ventilated sheds Traditional barns and sheds have sides that are partially open with wire netting. Large curtains are raised and lowered to manipulate the temperature and ventilation rate. Roof vents and ceiling fans are also used, and the chickens are misted to increase evaporative cooling. Naturally ventilated sheds are cheaper to run and maintain, but are not as effective at maintaining optimum climatic conditions. Tunnel-ventilated sheds One end of the tunnel-ventilated shed is fitted with large fans that draw air through the shed from the other end, through cooling pads. Temperature sensors adjust the fan rate as often as every three minutes. These sheds use more electricity and are more expensive to maintain. However, they are very effective at maintaining an optimum shed environment. ASSESSING BROODER CONDITIONS PURPOSE To regularly assess the microclimate inside a brooder to ensure chick health and comfort RISK ASSESSMENT LET’S ENGAGE Brooder lights can cause burns. Take care when taking measurements near lights. Wash hands before and after this activity. MATERIALS Brooder with chicks Thermometer METHOD 1 Assess the temperature at various times during brooding. Choose a spot in the middle of the brooder away from direct heat. 2 Assess the behaviour of the chicks. Copy the table below and record your observations. Age (days) Temperature Temperature of Behaviour of chicks requirement (°C) brooder (°C) 0 34 7 30 14 26 21 22 28 20 DISCUSSION 1 What adjustments are needed to be made to the heat source during brooding? 2 Describe the behaviours of the chicks when the temperature was too warm or too cold. 3 How could brooder temperature be monitored in large-scale enterprises? 9780170443111 CHAPTER 13 – POULTRY 367 Enterprise management CHAPTER 13 Breeding and genetics Commercial layer and meat birds are the result of several generations of careful breeding. They possess a combination of excellent production traits inherited from specifically selected parents, grandparents and great-grandparents. Hybrids look and behave in predictable ways and are very similar to each other. This is important because commercial egg producers want their eggs to be identical. Meat producers need birds that grow predictably and produce easily processed carcases. Oviduct Shell Ovary Fimbrium gland Magnum Isthmus or uterus Infundibulum Vagina Egg turns around in cloaca before being laid Next yolk released Cloaca in 1 hour Ovum fertilised, Albumen Membranes Shell chalazae added added formed added 23–26 hours Figure 13.15 The reproductive organs of a hen Breeder farms house breeding hens and roosters together and collect eggs for incubation. cloaca the body cavity of a hen or rooster Eggs are produced in the hen’s reproductive tract, as shown in Figure 13.15. containing the ends of the digestive, reproductive and DID Roosters do not have a penis. Mating involves a cloacal kiss where the rooster urinary tracts YOU and hen press their cloacae together to transfer sperm. KNOW WS Homework Learn more about eggs by completing the worksheet AG IN FOCUS Chicken eggs on NelsonNet. BREEDING MEAT CHICKENS Identify The chickens we eat are actually the fourth generation of a breeding program that continuously supplies new meat birds. > 368 AG TECH FOCUS 9780170443111 > Understand Fertile eggs are imported Breeding meat chickens from overseas and hatched to produce Fertile eggs imported from nucleus stock overseas great- grandparent birds. These birds are very valuable and are kept in breeder farms in isolated, Great-grandparents strategic locations around Australia. The next generation of chicks are transferred Grandparents are then mated from the hatchery to with other grandparent lines another breeding farm, and the process is repeated until the fourth generation hatch. This Parent breeders last generation of hybrids are raised for meat. Discussion 1 Discuss why great- Meat chickens grandparent breeder farms would be located in isolated, Figure 13.16 The meat chicken’s family tree strategic locations. 2 Breeding birds must be kept in optimal condition. Describe some of the ways these birds would be cared for to ensure they are healthy and productive. Nutrition Digestive system Oesophagus Chickens must swallow their food whole because Crop they have no teeth. The crop stores and softens Proventriculus food before passing it down to the proventriculus, Gizzard Pancreas or stomach, where acid and enzymes are used for chemical digestion. The ventriculus, or gizzard, is a Duodenum Small intestine strong, muscular organ that grinds the food. Grit is fed to birds to help this mechanical digestion. Caeca Large intestine The small intestine is the site of further chemical digestion and the absorption of nutrients. Cloaca Water is absorbed in the large intestine, then faeces Figure 13.17 The digestive system are passed out of the cloaca. of a bird Feeding Birds need protein for growth and development, while carbohydrates and fats are important energy sources. Layer birds must have high levels of calcium in their diet for eggshell production. Birds housed indoors need additional vitamins and minerals because they do not have access to sunlight or green feed. Hens housed in pastured and some free-range production 9780170443111 CHAPTER 13 – POULTRY 369 systems have access to a range of natural feeds, including insects and other invertebrates as well CHAPTER 13 as a variety of plant material. Poultry feed is usually based on a combination of ingredients including: ∙ cereal grains, such as wheat and sorghum (these are carbohydrate sources) ∙ protein meals, including oilseed and meat meals ∙ fats and oils, such as tallow and canola oil ∙ minerals and vitamins, including calcium and phosphorus. The ingredients are mixed together to meet nutritional needs and are processed into pellets, crumbles or mash at feed mills. Layers and meat chickens have very different nutritional requirements. Table 13.1 Nutritional requirements for meat chickens Nutrients Starter (0–10 days) Grower (11–24 days) Finisher (>25 days) Protein (%) 22–25 21–23 19–21 Energy (Kcal/kg) 3010 3175 3225 Calcium (%) 1 0.9 0.85 Table 13.2 Nutritional requirements for layers Nutrients Starter (0–6 weeks) Grower (6–15 weeks) Point of lay (15 weeks–adult) Protein (%) 20 17.0 16 Energy (Kcal/kg) 2860 2900 2850 Calcium (%) 1 1 2.75 INDUSTRY IN FOCUS POULTRY NUTRITIONIST Identify Poultry nutritionists are animal scientists who formulate diets for birds in different production systems. Knowledge of biology, animal behaviour, biochemistry and economics is essential to this profession. Most poultry nutritionists have tertiary qualifications (a university degree, at least) in animal or agricultural science. When formulating diets, poultry nutritionists need to take into consideration the nutritional needs of the birds, the type of stage of production and their taste preferences. Diets need to be cost effective, so an understanding of grain markets and seasonal conditions is also important. Some poultry nutritionists work for large poultry or feed companies, whereas others act as consultants to farmers, helping them make the best decisions about how to feed their animals. Discussion 1 Outline the role of a poultry nutritionist. 2 What qualifications do poultry nutritionists need? 3 A number of factors need to be considered when formulating a poultry diet. Describe the factors and explain why these factors are important. 4 Design a nutritionally balanced feed for chickens at two different stages of development using an online ration tool. Ration tool 370 AG TECH FOCUS 9780170443111 Housing Artificial light is used to manipulate egg production and growth rates. Hens generally lay more eggs leading up to summer as day length increases. Artificial lighting can be used to simulate these conditions. Most layer birds are exposed to 15 hours of light per day. This can be achieved by having timed lighting before sunrise and after sunset in free-range systems or providing artificial light for the entire 15-hour period in cage and barn systems. Meat birds are exposed to up to 23 hours of light per day to encourage feeding. Research suggests there may also be a link between the colour of the light and the behaviour and growth rates of chickens. DID Lights are kept dim for meat chickens because this makes them docile and YOU calm. KNOW LIGHT COLOUR AND GROWTH RATES PURPOSE 3 Install the ceramic heat lamp and To determine the effect of different light the cool tone LED lamp in the other LET’S EXPERIMENT wavelengths on poultry growth brooder. 4 Compare brooder temperatures and HYPOTHESIS adjust the heights of the heat lamps Do you think light colour will have an to achieve similar conditions in both effect on growth rates? If so, do you brooders. Repeat this procedure think red or blue light will be related to as the chicks mature and their higher rates of growth? temperature requirements change. 5 Randomly select chicks from each RISK ASSESSMENT brooder. Weigh them at regular intervals and record weights in a table. Brooder lamps can get very hot. Ceramic lamps do not emit visible RESULTS light but can still cause burns. 1 Construct a table to record the average Wash hands before and after weight of each group over time. handling chicks. 2 Draw line graphs to show average growth rates over time for each light MATERIALS group. Two brooders or brooding areas DISCUSSION One ceramic brooder lamp One infrared brooder lamp 1 Interpret your results. Was there a difference between the groups? One cool-tone LED lamp 2 How could you improve on this Chicks experiment to make it more reliable Electronic scales and fair? 3 What recommendations would you METHOD give to producers regarding light 1 Set up the two identical brooders colour for brooders? with feed, water and litter. 2 Install the infrared heat lamp in CONCLUSION one brooder. Was your hypothesis correct, incorrect or partially correct? 9780170443111 CHAPTER 13 – POULTRY 371 Records and financial management CHAPTER 13 Feed conversion ratio Records allow farmers to make informed decisions based on data. Records of costs and volumes of feed can be used to work out the feed conversion ratio (FCR) of meat birds. The FCR is a measure of how efficiently an animal can convert feed into weight gain. Weight of feed (kg) Feed conversion ratio = Weight gained (kg) The lower the FCR, the more efficiently the food is converted to weight gain. Meat chickens have FCRs of approximately 1.8, meaning they need to eat 1.8 kg of feed to gain 1 kg in weight. The type of feed also affects the FCR. Cheaper feeds may be poorer quality and contain less protein and energy than more expensive feeds, meaning more needs to be fed to achieve target weights. Gross margins AG IN FOCUS GROSS MARGINS FOR CAGE EGGS AND BARN EGGS Identify Gross margin analysis can be used to determine the relative profitability of different enterprises. Cage and barn eggs have different production costs, but they also sell for different prices. Understand Table 13.3 lists some of the most significant variable costs involved in producing cage and barn eggs. Table 13.3 Variable costs to produce one dozen eggs in cage and barn production systems Variable cost Cage production ($) Barn production ($) Feed 0.68 0.73 Replacement pullets 0.21 0.27 Labour 0.04 0.10 Energy 0.03 0.03 Medicine and other chemicals 0.05 0.06 Total variable costs ___________ ___________ Cage eggs generally sell for a lower price than barn eggs. In this example, we will that assume that the cage eggs have sold for $3.50 per dozen, while the barn eggs have sold for $4.50 per dozen. These figures represent the gross income for one dozen eggs in each production system. Discussion 1 Calculate the gross margin per dozen eggs for both cage and barn production using the formula: Gross margin = Gross income − Variable expenses 2 Which production system has the higher gross margin for one dozen eggs? > 372 AG TECH FOCUS 9780170443111 > 3 Cage production can occur at a huge scale, with up to 100 000 birds in a shed. Barn production systems usually house up to 30 000 birds per barn. How many more eggs can a cage egg farmer produce from one shed, compared with a barn producer? 4 Explain why, even though barn production has a higher gross margin per dozen eggs, cage production is often more profitable. 5 What might be a better way to measure gross margins, rather than per dozen eggs? LET’S REVIEW LOOKING BACK 1 Why were poultry farms traditionally near towns or cities? 2 Identify different ways temperature can be adjusted in a brooder. 3 Why is it important to keep birds at optimum temperature? 4 Compare naturally ventilated and tunnel-ventilated sheds in terms of their energy use, maintenance and effectiveness in controlling shed climate. 5 Contrast the nutritional requirements of layers and meat birds at different stages of production and explain these differences. FOR YOU TO DO 1 Calculate the feed conversion ratio of your brooding chickens. 2 Examine bags of feed used for the school poultry. Determine what stage of production they are for and compare the nutritional contents and ingredients. 3 Robots have many possible roles in poultry production. Identify one issue in poultry production and design a robot to address the problem. Possible issues include feed waste and spoilage, identification of sick or injured birds, or environmental enrichment of cage and barn systems. Make a (non-working) model of your robot using recycled materials and present it to your class. TAKING IT FURTHER 1 Assess the school’s poultry housing. Examine climatic and housing factors, including the susceptibility of the school birds to predators. 2 Draw up plans for a new and improved poultry house for the school’s chickens. 3 Investigate sanitation robots and their use in the poultry industry. Compare the effectiveness of sanitation robots and human workers in keeping poultry sheds clean and disease-free. 9780170443111 CHAPTER 13 – POULTRY 373 13.5 Pests and diseases CHAPTER 13 Pests External parasites WS Lice and mites are common external parasites of chickens. Lice feed on skin scales, feathers and scabs. They can survive for up to a week in the environment, especially in litter. Mites are blood Homework suckers and can survive even longer off their host. Find out about red poultry mites by completing the worksheet Integrated pest management (IPM) is used to control lice and mites. IPM uses a variety Integrated pest management for red poultry mites on NelsonNet of different methods to control pests to avoid economic loss and reduce the likelihood of resistance building up in pest populations. Table 13.4 Integrated pest management for lice and mites Chemical controls Physical controls Cultural controls Biological controls ∙ Insecticides such ∙ Destroy or remove ∙ Examine birds ∙ Predatory mites as permethrin any boxes or regularly. that eat chicken lice containers infested ∙ Quarantine new and mites. birds have used. and infested birds. ∙ Exclude wild birds that may be infested. Internal parasites Coccidiosis is a gastrointestinal disease caused Alamy Stock Photo/The Natural History Museum by coccidia protozoa. These small single-celled organisms damage the lining of the gut wall, causing bloody diarrhoea. Infected birds are often hunched up with their feathers fluffed due to pain. Mild infections may cause no signs, and birds might become immune to the parasites. However, young chicks and birds that are stressed or otherwise ill are very susceptible to coccidiosis. The coccidia oocysts can be spread by direct oocysts small capsules containing the reproductive contact and through infected faeces. They are coated cells of protozoal organisms with a tough wall and can survive for long periods in the environment. Cleaning and disinfection of sheds between batches of chickens is important in Figure 13.18 Electron micrograph image eliminating coccidia oocysts. Some chicken feeds of a poultry mite contain a coccidiostat, which is a medication that helps control coccidiosis. Diseases Marek’s disease Marek’s disease is caused by a virus that enters via the respiratory tract. Affected birds may become paralysed, display neurological signs and develop tumour-like lesions on their internal organs and feather follicles. Once infected, birds are carriers for life, shedding the 374 AG TECH FOCUS 9780170443111 highly infectious virus in their feather dander. Marek’s virus can survive for months in the environment but cannot be transmitted from a hen to her chick through the egg. There is no treatment and infected birds should be culled. A vaccine against Marek’s disease is often given to new chicks at the hatchery. The vaccine does not prevent infection with the disease but does reduce the amount of virus shed into the environment. Marek’s disease can be spread via contaminated clothing and vehicles, so on-farm biosecurity is an important preventative.Visitors to poultry farms should wear disposable overalls, chicks should be reared separately and disinfection of sheds should be carried out between batches of chickens. Newcastle disease Shutterstock.com/marcovarro Newcastle disease is caused by a virus and infects a range of birds including chickens, turkeys, pigeons and parrots. It causes respiratory signs including shortness of breath, as well as diarrhoea, collapse and death. Most birds infected with Newcastle disease die, but those who survive the longest usually show nervous system signs including twisted Figure 13.19 Layer hen suffering from Newcastle disease necks. The virus is highly contagious and spread via direct contact with infected birds. Contaminated equipment, carcases, water, food and clothing are also potential sources of infection.Viral particles are destroyed by sunlight, heat and acid, but can survive for weeks in cool, contaminated sheds or in manure. Australia was declared free from virulent Newcastle disease in 2001, although there have been minor outbreaks of mild strains since then. Newcastle disease is a notifiable disease, meaning that there is a legal obligation to inform authorities if birds are known or suspected to be infected with the virus. Outbreaks are managed according to the National Disease Management Plan, with slaughter of exposed or infected birds and disposal of infected products. Strict quarantine and movement controls are also placed on areas where suspected or confirmed cases have been reported.Vaccination of commercial flocks is compulsory in Australia. Newcastle disease has not been reported in New Zealand. DID New Zealand is the only country in the world free of the ‘big three’ YOU bird diseases: Newcastle disease, avian influenza and infectious KNOW bursal disease. 9780170443111 CHAPTER 13 – POULTRY 375 LET’S REVIEW CHAPTER 13 LOOKING BACK 1 How do lice and mites feed on chickens? 2 When are chickens most vulnerable to coccidiosis? 3 Describe the signs of Marek’s disease and Newcastle disease. 4 Give three examples of biosecurity measures that can be used to prevent poultry pests and diseases. FOR YOU TO DO 1 Examine the school chickens for signs of lice and mites. 2 Discuss the advantages and disadvantages of using integrated pest management rather than relying solely on chemicals. 3 Examine chicken feed from the agricultural plot to determine whether it contains coccidiostats. TAKING IT FURTHER 1 Research one other pest or disease of chickens and write a report outlining signs of infection, prevention methods and treatment options. 2 Assess the school’s poultry housing in terms of biosecurity and disease prevention. Use the Farm Biosecurity app to determine the school’s biosecurity risks. Farm Biosecurity app 13.6 Social and ethical issues Are cage eggs cruel? Many consumers are concerned about the welfare of hens in cage production. The most common concern is that birds are unable to express natural behaviours. Chickens exhibit a number of natural behaviours including preening, foraging, nesting, dust bathing and perching. Chickens also have social behaviours, including a pecking order. Birds establish social hierarchies and can recognise up to 30 individuals in their group. Once they know their place, pecking and fighting is rare. However, if new birds are introduced or if group numbers exceed 30, birds can be caught in a continuous battle to establish their pecking order. Hens in cage production are kept in a small groups and can establish a stable pecking order. Barn, free- range and pastured birds often display more fighting and sustain more injuries due to continual social stress. Rates of cannibalism and death are also higher. LET’S DISCUSS 1 Which do you consider more important: the ability to express natural behaviours or safety from injury and stress? 2 Is cage or free-range production more ethically acceptable? 376 AG TECH FOCUS 9780170443111 Beak trimming and blinders Beak trimming involves removing part of the top beak to control feather pecking, injury and cannibalism. It is performed on day-old layer chicks, and then is sometimes repeated at two to three months of age. Beak trimming can be painful and can cause problems with feeding. Blinkers, blinders and peepers are devices that are placed on a bird’s beak to interfere with their vision and deter them from feather pecking. Red contact lenses have also been used to reduce aggressive behaviour, but can lead Shutterstock.com/Quirky China to irritation, infections and eye damage. The Model Code of Practice for Poultry states that beak trimming should be avoided if possible, and producers should select birds for reduced feather pecking and aggressive behaviour. Contact lenses are not to be used, and blinkers must be avoided in cage systems and when nesting boxes are off the ground. Figure 13.20 Blinkers can be used to reduce feather pecking. LET’S REVIEW LOOKING BACK 1 Identify some natural chicken behaviours. 2 Which behaviours are chickens unable to express in cage systems? 3 Why is beak trimming performed and what are the alternatives? FOR YOU TO DO 1 Observe the school chickens and record the occurrence and frequency of natural behaviours. 2 Conduct a class debate on the ethics of cage production. 3 Research designs of blinkers and design some human-sized examples for students to test. TAKING IT FURTHER 1 Investigate furnished cages and other methods of environmental enrichment for cage hens. 2 Research one other ethical issue that is addressed in the Model Code of Practice. Model code of practice 9780170443111 CHAPTER 13 – POULTRY 377 13.7 Sustainability CHAPTER 13 Sustainable practices and methods Using chickens to repair soil INDUSTRY IN FOCUS LACHIE’S FARM FRESH EGGS Credit: Jo Broad Figure 13.21 Lachie Broad with his maremma, Ellie Identify Lachie Broad runs a pastured egg business in Bodalla, on the NSW south coast. His hens are housed in a purpose-built solar-powered chicken caravan with roosts and nesting boxes. Once laid, eggs roll from the sloping nesting boxes directly onto a conveyer belt, reducing soiling of shells and making collection easy. The caravan is moved in rotation around the family’s dairy farm where the hens have constant access to nutritious irrigated pasture. Lachie sells eggs at a number of local farmers markets and in some retail businesses. Understand When hens are placed on pasture after dairy cattle, they scratch and distribute cow manure, as well as eat insects, including parasites and fly larvae. They also produce their own manure that adds to the soil organic matter and provides nutrients for plant growth. Green feed such as pasture provides hens with chemicals called xanthopyhlls that give egg yolks a deep yellow to orange colour. Apart from producing attractive eggs, pastured production allows hens to explore their natural environment and express innate behaviours. >  378 AG TECH FOCUS 9780170443111 > Lachie’s maremma dog, Ellie, protects the flock from eagles and foxes. The hens have bonded with their guardian dog and run straight to her if she barks a warning. Discussion 1 Explain the advantages of pastured production. Watch the Landline episode 2 Draw a mind map to show interactions between the pastured hens and other about another farmer using pastured production to enterprises and systems on Lachie’s farm. regenerate the soil. How do 3 How has Lachie’s system dealt with some of the normal disadvantages of their strategies compare to Lachie’s? free-range and pastured egg production? The impact of feeding chickens Feed is the most expensive input for poultry production and has the greatest environmental impact. Selective breeding of meat chickens to have high growth rates allows farmers to use less feed and reduce costs. Compared with other farm Table 13.5 Feed conversion ratios of some farm animals animals, chickens convert feed into Animal Feed conversion ratio meat very efficiently. While it takes Beef cattle (steers) 6.0 6 kg of feed to produce 1 kg of beef, Lambs 5.5 the same amount of chicken meat can Pigs 2.5 be produced with just 1.8 kg of food. Chicken meat 1.8 LET’S DISCUSS 1 What inputs are used to grow, harvest and process cereal grains and oilseed crops for feed production? 2 What are some possible environmental impacts of growing these crops? Sustainable technology Using wastes to improve soils and make energy Soiled poultry litter can be used as a soil conditioner. If used appropriately, it is a rich source of nutrients and organic matter. Some used litter is processed into pellets and sold as organic fertiliser. Unprocessed litter is often purchased in bulk by other farms for pasture improvement. Care must be taken when using bulk litter because it may contain animal proteins in the form of spilled feed, feathers or even dead birds. It is illegal to feed animal proteins to ruminant animals such as cattle and sheep due to the potential risk of disease, including mad cow disease (Bovine spongiform encephalopathy). biofuel fuel made from Poultry litter can also be processed and used as a biofuel. Spent litter is burned at living things 400–500°C to produce carbon dioxide and methane gases. These gases can then be combusted to produce heat and generate electricity. The power generated this way can be used to heat sheds or run ventilation fans. The remaining solids can then be used as fertiliser or soil amendments. Litter biofuel is a renewable energy source and an alternative to fossil fuels. 9780170443111 CHAPTER 13 – POULTRY 379 Sustainable decision-making CHAPTER 13 Cage eggs have smaller carbon footprints than free-range systems because the birds produce eggs much more efficiently. In the short term, cage systems produce more eggs for less inputs using less land. Soiled litter and other waste products from intensive systems such as cage production must be disposed of appropriately. Poultry wastes that are disposed of inappropriately can lead to long-term consequences such as contamination of soil and groundwater. Soiled litter and manure can also release large amounts of greenhouse gases when left to decompose in piles. carbon footprint the total While free-range and pastured production uses more land to produce less, the greenhouse gas emissions environmental impact is not a simple equation. Pastured egg production, for example, adds caused by an individual or activity poultry manure to the soil in the long term. Much of the carbon in the manure is then locked up in the soil rather than being released into the atmosphere. Animal welfare advocates argue that free-range chickens have a higher quality of life than caged hens and believe this should be taken into account when comparing systems. LET’S DISCUSS 1 Which is more important: efficient production or animal welfare? 2 Compare the short-term costs and long-term consequences o