Chickens that are grown for meat production (also called broiler chickens) are genetically very different from layer hens (which are bred to produce eggs). Meat chickens have been selectively bred over many generations to grow and gain weight very rapidly, with birds ready for processing at 4-6 weeks old. A younger meat chicken, called a ‘spatchcock’ is processed at 21 days of age.
The rapid growth rate can cause severe welfare problems. These welfare problems include leg disorders, a condition called ‘ascites’ (accumulation of fluid in the abdominal cavity) and heart failure. Birds often become so heavy that they suffer from leg weakness and joint problems. Their legs may be unable to support them, leaving them unable to access food and water. Birds can also suffer from hock, breast and foot burns due to contact with damp litter. The genetics of meat chickens needs to change in order to avoid the welfare issues of leg problems and heart failure, and the resulting mortality.
Environmental conditions inside the shed
Atmospheric ammonia can build up in the shed, particularly if the litter becomes damp due to the accumulation of droppings. High concentrations of ammonia in the air can cause abnormalities in the eyes and respiratory tract. Litter management and shed ventilation are important to maintain good litter quality and avoid these issues. Birds that are injured or sick and/or unable to reach food and water need to be euthanased, and the handling and method of euthanasia need to be humane. Inadequate lighting can also lead to eye abnormalities.
Stocking density is another welfare issue, especially at the end of the growing period. Chickens may experience a lack of exercise due to their large body sizes, low lighting levels, lack of a stimulating environment, and lack of space, which increases the incidence of lameness. This, in turn, increases the birds’ contact with the litter, causing foot pad burn, hock burn and breast blisters if the litter is not well managed. Chickens can die from heat stress caused by the cramped conditions in the shed.
Expression of natural behaviours
Chickens have behavioural needs to perch, forage and dustbathe, which need to be accommodated by the provision of good quality litter, perches, and pecking objects.
Catch and transport
Once the chickens are ready for processing (determined by weight), they are placed into crates and transported to the processing plant. Chickens can be ‘caught’ by hand or by machine for placing into the transport crates. If caught by hand, people usually catch a few chickens at a time by the legs and put them into crates. There is the potential for chickens to be handled roughly or for body parts to be caught in the transport crates. The catching process may cause the birds pain since they are caught by the legs, and meat chickens frequently experience leg disorders and painful joint conditions. During transport, chickens are not provided with feed or water. Some birds may die from heat stress or from being crushed during transport.
Upon arrival at the slaughtering plant, chickens are removed from their crates and shackled, upside down, by their legs on a conveyor system. They are then stunned (rendered unconscious) in an electrical water bath and have their neck cut to allow bleeding out. They are then plucked, cleaned, processed and packed. Before slaughter, the birds may experience suffering and pain, particularly due to rough handling or shackling of birds with broken bones, leg disorders or bruises. There are also several welfare risks associated with electrical water bath stunning, including pre-stun electric shocks and ineffective stunning.
Controlled atmosphere stunning (CAS) and low atmospheric pressure stunning (LAPS) are two alternatives to electric waterbath stunning. CAS uses gases to stun the birds, and this system is widely used in Australia. LAPS is a newer form of stunning where birds are placed in a chamber and the atmospheric pressure is gradually reduced, causing birds to lose consciousness gradually and painfully and is not yet in use in Australia. Both CAS and LAPS have the benefit of not needing to handle and shackle live birds, reduce stress, and allow greater uniformity of the stun between birds.
Since meat chickens grow at such a rapid rate and reach slaughter weight at such an early age, the birds which are used to breed meat chickens are also genetically predisposed to grow very fast and eat a lot of food. These breeder birds therefore are feed and water restricted, are in a chronic state of hunger, and are kept in low light to prevent abnormal behaviours.
What can be done to address these welfare issues?
Significant welfare problems can be prevented by selecting for a slower rate of growth, good stockpersonship and handling, reducing stocking density in the sheds, providing adequate lighting, and providing an environment that encourages natural behaviours.
The RSPCA is working to improve the welfare standards set out in the Model Code of Practice for the Welfare of Animals: Domestic Poultry, as well as the welfare standards for the transport and slaughter of meat chickens.
The RSPCA also has an Approved Farming Scheme for meat chickens which stipulate specific conditions in which birds must be kept. To learn more about the RSPCA Approved Farming Scheme for meat chickens, visit the RSPCA Approved Farming Scheme website.
To learn more about humane farming and shopping for humane food visit Choose Wisely.