A knacker is a person in the trade of rendering animals that have died on farms or are unfit for human consumption, such as horses that can no longer work. This leads to the slang expression "knackered" meaning very tired, or "ready for the knacker's yard", where old horses are slaughtered and the by-products are sent for rendering. A knacker's yard or knackery is different from a slaughterhouse, where animals are slaughtered for human consumption. In most countries, knackery premises are regulated by law.