Physiological and behavioural responses of the domestic hen to hypoxia.

Physiological and behavioural responses of adult hens and chicks were monitored in atmospheric and increasingly hypoxic conditions to investigate whether anoxic killing was a suitable alternative method for use in the slaughter industry. All birds were placed in a perspex box for easy observation and nitrogen gas was slowly administered when subjecting birds to anoxic conditions. When subjected to decreasing oxygen concentration adult birds slowly became unconscious, without showing any signs of distress, until respiratory failure supervened. Chicks showed similar results but loss of motor control was observed while still conscious which might cause some distress. Further investigations are suggested to alleviate this problem.