Commercial turkeys raised for meat production may at times need to be euthanased on-farm because they are weak, sick, injured or unable to walk, and will not recover with treatment.
As with all euthanasia of animals, it is important that the method used is humane, meaning the method chosen either kills the animal immediately or renders them insensible until death without causing pain, suffering or distress. For sick and injured animals, it is important that they are killed without delay, to prevent further stress or suffering.
What are the animal welfare issues associated with cervical dislocation?
The most common form of on-farm euthanasia for poultry in Australia is cervical dislocation, where death occurs by cerebral ischemia (insufficient bloody flow to the brain) if performed correctly.
There are welfare concerns with cervical dislocation and the time taken for unconsciousness to be achieved. The scientific evidence indicates that cervical dislocation does not cause immediate insensibility (loss of consciousness) in birds, therefore there may be a short period of time when birds experience pain prior to death. In large birds, the correct technique of cervical dislocation is very difficult to achieve making it an ineffective method of euthanasia. For this reason, cervical dislocation should only be used for birds <3kgs [1].
What are alternative methods of euthanasia?
A more humane method of euthanasia than cervical dislocation, is a non-penetrating captive bolt device. These cause death by a percussive blow from the bolt that produces significant damage to the skull and brain, resulting in rapid loss of consciousness and death [2]. When using a captive bolt, it is important that it is specifically designed and appropriate for the size of bird, and that birds are restrained appropriately to allow for accurate positioning (placement and angle) of the device on the bird’s head.
On-farm carbon dioxide gas killing is another alternative to cervical dislocation when appropriate equipment and non-aversive gas concentrations are used. Carbon dioxide is commonly used at meat chicken abattoirs in controlled atmosphere stunning systems. At high concentrations, carbon dioxide gas results in unconsciousness and eventual death through hypoxia (lack of oxygen). High concentrations of carbon dioxide gas have been shown to be aversive (extremely unpleasant) to poultry. Therefore, on-farm gas killing should be done using at least a two-phase method whereby non-aversive carbon dioxide concentrations are used until birds have lost consciousness followed by high concentrations to ensure death [1].
Non-penetrating captive bolt devices and gas killing offer more humane options for on-farm euthanasia especially in turkeys where, due to their large size, cervical dislocation is ineffective. Current barriers to the adoption of alternative on-farm euthanasia methods include access to the technology, portability, concerns about worker health and safety, and training required on farm. These barriers must be urgently overcome to ensure poultry euthanasia is carried out according to current best practice.
References
[1] EFSA (2019) Scientific opinion: killing for purposes other than slaughter – poultry. EFSA Journal 17(11),5850.
[2] Erasmus M, Lawlis P, Duncan I et al (2010) Using time to insensibility and estimated time of death to evaluate a non-penetrating captive bolt, cervical dislocation, and blunt trauma for on-farm killing of turkeys. Poultry Science 89:1345-1354.
