Specific regulations govern the method by which an animal must be slaughtered before it is permitted. So complex and minute are the regulations that the slaughter must be carried out by a carefully trained and licensed shohet. It is his duty both to slaughter the animal, and to carry out an examination (bedikah). Should a defect be found in some of the organs, such as the brain, the windpipe, the esophagus, the heart, the lungs, or the intestines, the animal is terefah, and forbidden for consumption. Defects are normally classified under eight categories (Ḥul. 43a): nekuvah, perforated organ walls; pesukah, split pipes; netulah, missing limbs; haserah, missing or defective organs; keru'ah, torn walls or membrane covers or organs; derusah, a poisonous substance introduced into the body, when mauled by a wild animal; nefulah, shattering by a fall; shevurah, broken or fractured bones. It is assumed in the Talmud that any of these defects would lead to the death of the animal within one year (Ḥul. 3:1). Only if the animal has none of these injuries, is it pronounced kasher. After shehitah, it is suspended head down, so that as much blood as possible may drain. Should various sections of the animal have been removed before the bedikah has taken place, the animal is usually considered kasher. This rule is based on the fact that the majority of animals are usually found, after bedikah, to be kasher (Ḥul. 11a–b). This rule, however, does not apply if the lung has been removed. Since a large minority of animals do suffer from lung diseases that portion of the body must always be examined and if that is impossible the animal is considered terefah. Shehitah and bedikah of poultry is carried out in the same careful manner. The same laws of terefah apply but there is no need for examination except of the intestines. There are no specific rules concerning the method by which permitted fish are to be killed.