The Humane Methods of Slaughter Act (HMSA) requires that humane methods of slaughtering and handling livestock in connection with slaughter be used. Livestock animals, such as cattle, calves, horses, mules, sheep, swine, and goats, must be rendered insensible to pain before being shackled, hoisted, thrown, cast, or cut. This may be achieved by electrocuting the animals, shooting them in the head with a firearm or captive bolt stunner, or gassing them with carbon dioxide gas. Which methods may be used depends on the species of animal involved. HMSA does not apply to poultry, and therefore, does not require the humane handling and slaughtering of domestic birds. HMSA also excludes animals killed in ritual slaughter to avoid unconstitutionally hindering the practice of religion under the First Amendment.
To comply with HMSA’s requirement of humane handling of livestock in connection with slaughter, regulations mandate that animals be driven at a normal walking speed, and forbid driving animals using anything that could injure them or cause unnecessary pain. Livestock pens, driveways and ramps must also be constructed in such a way so as to prevent injury or pain to the animals. HMSA makes special provisions for the handling of nonambulatory livestock (animals that cannot walk). For example, such animals must be separated from the others and provided with a covered pen while they await disposition. Conscious nonambulatory animals may not be dragged, but rather must be moved in a humane manner. A violation of these provisions may result in criminal and civil penalties, such as a fine and/or imprisonment.
Unfortunately, HMSA lacks a general enforcement provision. § 1903 had originally prohibited the federal government from purchasing livestock products made from animals slaughtered inhumanely, but it was repealed in 1978. It is still possible for inspectors to enforce the law by leveraging their authority to halt operations until compliance with HMSA is achieved.
Ultimately, it is difficult to judge how effective HMSA is at ensuring humane handling and slaughter due to a lack of enforcement and due to the fact that slaughterhouses are not open to the general public.