The pros and cons of various on-farm culling techniques

This Defra-funded project will examine the welfare implications of existing and novel on-farm culling methods for small numbers of poultry that are feasible to use on commercial poultry units, e.g. are portable, simple to use with minimal training, and require little equipment. Currently, the most common and simple method is manual cervical dislocation, because it requires no equipment and is relatively easy to learn. Cervical dislocation severs the vertebral column from the cranium and ruptures the blood vessels that supply the brain. However, loss of consciousness may not be instantaneous, which has serious welfare implications. Alternative, mechanical techniques include the “Armadillo” where a spike penetrates and destroys the brain stem, but no scientific research has been undertaken to assess its effectiveness, and devices which are designed to stretch and twist the neck, such as Semark pliers or Burdizzo, but these may not sever the carotid arteries but merely crush the neck instead, for which reason they are banned as a method of stunning in the EU from 2013.
There are also pneumatic or cartridge powered percussive devices that apply a blow to the head, resulting in the immediate loss of consciousness and, when applied correctly, death. Although possible to shoot turkeys unrestrained, all other poultry require restraint to allow accurate positioning of the gun. This becomes increasingly difficult for smaller birds and ones which are highly mobile. In practical terms, both pneumatic and cartridge-powered devices have implications for cost, logistics/convenience and health and safety implications for operatives. In FAWC’s 2009 recommendation, they expressed a desire for further refinement and development of such methods.
We will review current and novel on-farm culling methods, in order to select methodologies to test during the project. We will then develop a robust and validated description of the visible signs and reflexes that are associated with brain indicators of loss of consciousness and death. Both the reviewed methods and some preliminary data on indicators of death will be presented at the Symposium. These visible signs and reflexes plus brain state indicators will then be used to assess how quickly the various methods induce loss of consciousness and death. Next, we will test the best methods under field conditions, using various bird types and different operators. Finally, we will collaborate with HSA to update guidelines on the best practice for killing poultry, including mitigation strategies where necessary.