Stunning systems of poultry species

Introduction In the distant past large animals were sometimes stunned by a heavy blow on the head where poultry was decapitated before slaughter During the last century concern for animal welfare increased. Concussion stunning was deemed not satisfactory, and improved stunning methods were developed. Stunning by captive bolt was introduced at the end of the 19th century, electrical stunning at the end of the 1920's and CO2-gas stunning in the 1950's. A basic requirement for humane slaughter of animals including poultry is that they should be stunned, rendered unconscious and insensible, prior to slaughter by exsanguination. Under commercial conditions, red meat animals (horses, ruminants and pigs) are stunned using either a penetrating captive bolt, non-penetrating concussion bolt, electric current or carbon dioxide gas, poultry species are stunned using electrified water bath. There are two main reasons for this common practice in poultry. Firstly, it may be difficult to apply captive or concussion bolt owing to a very small target area (head) for shooting in poultry without compromising bird welfare under commercial conditions. Secondly, the throughput rates required in medium to large chicken processing plants (killing 5 to 9 thousand birds per hour) can be easily achieved with water bath stunners rather than with captive bolt or concussion stunners. An alternative stunning system to the generally applied electrical water bath stunner for broiler chickens is gas stunning (CAS = Controlled Atmosphere Stunning). This method of stunning can eliminate the stress associated with uncrating and / or shackling of live birds prior to electrical stunning.