Poultry farming means 'raising various types of domestic birds commercially for the purpose of meat, eggs and feather production'. The most common and widely raised poultry birds are chicken. Chickens, turkeys, ducks, and geese are of primary importance, while guinea fowl and squabs (young pigeons) are chiefly of local interest. Whatever the production system, all management procedures with adult stock - during incubation and hatching, brooding of young chicks, and rearing of young meat and layer stock - should focus on meeting the birds' physiological requirements at all stages of life by providing an ideal physical environment, minimizing exposure to disease, meeting the birds' behavioral and social needs, and providing them with clean water and goodquality feed that satisfies their nutrient requirements. Animals eat to acquire the energy and building materials that they need to live and grow. Animals use energy to perform normal body functions such as breathing, walking, eating, digesting, and maintaining body temperature. Nutrients provide poultry the energy and material needed for the development of bone, flesh, feathers, and eggs. Water is often overlooked, but it is one of the most important nutrients. An animal can live without food longer than it can live without water. Water plays an important role in the body of an animal. Water softens feed and carries it through the digestive tract. Carbohydrates (compounds with carbon, hydrogen and oxygen) are an energy source for animals and make up the largest portion of a poultry diet. Proteins are used in the construction of body tissues such as muscles, nerves, cartilage, skin, feathers, beak, and so on. Egg white is also high in protein. Minerals play a role in bone formation, but minerals are also needed for several other important functions, including formation of blood cells, blood clotting, enzyme activation, and energy metabolism and for proper muscle function. Vitamins are a group of organic compounds that poultry require in small quantities. Despite the low requirement levels, vitamins are essential for normal body functions, growth, and reproduction.