is the process of rendering animals immobile or unconscious prior to their being slaughtered
for food. This process has been common for centuries in the case of cattle
, who were poleaxed
prior to being bled out. In the United Kingdom
more widely the development of stunning technologies occurred largely in the first half of the twentieth century.
Prior to humane slaughter pistols and electric stunners, pigs, sheep and other animals (including cattle) were simply struck while fully conscious. The belief that this was unnecessarily cruel and painful to the animal being slaughtered was the rhetorical justification for, in many countries, the compulsory adoption of stunning methods, almost all associated with modern technology. The discourse of progress and humanity in morals and technology were thus intimately intertwined. The Humane Slaughter Act of 1933 in Britain, for example, was specifically conceived not only to make stunning compulsory, but moreover to make particularly modern incarnations of stunning, such as the captive bolt pistol and electric tongs, the means by which it was achieved. The wording of the 1933 act specifically outlaws the poleaxe. The period is marked by the development of various innovations in slaughterhouse technologies, not all of them particularly long-lasting.
In modern slaughterhouses a variety of slaughter methods are used on livestock. Methodes include:
- Electrical stunning
- Gas stunning
- Percussive stunning
Electrical stunning is done by applying a current through the brain of the animal before slaughter. An epileptic shock is induced by overloading the neurons, which would render the animal incapable of feeling pain. It is a controversial subject however. With chickens for example, overstunning leads to bone fractures and/or electrocution which prevents bleeding of the animal. This negatively effects the quality of the meat therefore understunning is an attractive practice for slaughterhouses.
In the Netherlands for example, the law states that poultry must be stunned for 4 seconds minimum with an average current of 100 mA, which leads to systematic understunning.
With Gas stunning animals are exposed to a mixture of gases (CO2
for example, but historically CO or mustard gas
was used) to suffocate the creatures.
With Percussive stunning, a device which hits the animal on the head, with or without penetration, is employed. Such devices, such as the captive bolt pistol
, can be either pneumatic, or powder-actuated.
The Food and Agricultural Organisation (FAO)outlines
practical suggestions for humane handling and slaughter of livestock.