Nearly 30 million cattle, calves, sheep, pigs and around 900 million poultry are killed every year in the United Kingdom for meat.
How are farm animals slaughtered?
The slaughter process has two stages: stunning and sticking. The law requires all animals (except those intended for certain groups that practice religious slaughter), to be stunned before sticking.
How is stunning carried out?
When performed correctly, stunning causes an animal to lose consciousness, so that it can’t feel any pain until it is dead. The law states that, with few exemptions, all animals must be stunned before being stuck. Three main methods are used:
Captive bolt stunning is used on cattle, sheep and some pigs. A gun fires a metal bolt into the brain of the animal. The bolt does not kill the animal (stop the heart) but, if used correctly, causes the animal to lose consciousness immediately.
Electrical stunning is used on sheep, calves and pigs. A large pair of tongs is placed on either side of the animal’s head and an electrical current passed through the brain. Unlike captive bolt stunning, which usually causes irreversible unconsciousness, electrical stunning causes temporary loss of consciousness. With some electrical stunning systems the current is also passed through the heart, so that the animal is both stunned and killed. Poultry may also be stunned by passing them through an electrically-charged water bath (see below).
Gas stunning/killing involves the use of gas mixtures to kill pigs and poultry. Pigs are exposed to mixtures of air and carbon dioxide, with poultry exposed to mixtures of air and argon gas, until the animals are unconscious. The UK law states that animals must be killed, not just stunned, using this method.
What is sticking and how is it done?
In the case of mammals, once an animal has been stunned it is shackled by a hind leg and hoisted above the ground. The slaughterman sticks the animal (cuts its throat), using a very sharp knife, severing the major blood vessels in its neck/chest that supply the brain, ensuring rapid blood loss. Once enough blood has left the body, the heart stops beating and the animal is dead.
How are poultry slaughtered?
Because of the huge number of birds slaughtered each year (around 900 million) the process of slaughtering poultry is largely automated. After arriving at the slaughterhouse birds are usually removed from the plastic crates in which they were packed at the farm, and hung upside down by their legs on metal shackles on a moving conveyor belt. The birds move along the production line to the stunning water bath. When the bird’s head makes contact with the water, an electrical circuit between the water bath and shackle is completed, which stuns the bird. The conveyor belt then moves the birds along to a mechanical neck cutter, which cuts the major blood vessels in the neck.
Many chickens, hens and turkeys are now killed using gas mixtures. Birds remain in the plastic transport crates and are placed into the gas chamber where they remain until dead. This method avoids the need to handle and 'shackle' live birds, so has some welfare advantages.
What is religious slaughter?
In the UK, the Jewish and Muslim communities are exempt from a section of the law that requires all animals to be stunned before they are slaughtered. There are differences in the way animals are slaughtered by the Shechita (Jewish) and Halal (Muslim) methods, but both involve cutting the animal’s throat with a very sharp knife, in many cases without pre-stunning. Within both the Jewish and Muslim communities there are different interpretations of the religious laws. The Meat Hygiene Service (MHS) ‘Animal Welfare Review’ (March 2004) indicated that, at that time, the majority of cattle (but not other species) killed by the Shechita method received a post-cut stun, and that around 90 per cent of Halal slaughter involved pre-stunning.
More detailed information on all of the above is available in the information sheets on the right.