Ducks have been farmed for thousands of years, possibly starting in Southeast Asia. They are not as popular as the chicken, because chickens have much more white lean meat and are easier to keep confined, making the total price much lower for chicken meat, whereas duck is comparatively expensive and, while popular in the haute cuisine, appears less frequently in mass market food industry and restaurants in the lower price range.
Ducks are farmed for their meat, eggs, and down. A minority of ducks are also kept for foie gras production. In Vietnam, their blood is used in a food called tiết canh. Their eggs are blue-green to white depending on the breed.
Ducks can be kept free range, in cages, in barns, or in batteries. To be healthy, ducks should be allowed access to water, though battery ducks are often denied this. They should be fed a grain and insect diet. It is a popular misconception that ducks should be fed bread; bread has limited nutritional value and can be deadly when fed to developing ducklings. Ducks should be monitored for avian influenza, as they are especially prone to infection with the dangerous H5N1 strain.
The females of many breeds of domestic ducks are unreliable at sitting their eggs and raising their young. Notable exceptions include the Rouen Duck and especially the Muscovy Duck. It has been a custom on farms for centuries to put duck eggs under a broody hen for hatching; nowadays incubators are often used. However, young ducklings rely on their mother for a supply of preen oil to make them waterproof, and a chicken hen does not make as much preen oil as a female duck; and an incubator makes none. Once the duckling grows its own feathers it will produce preen oil from the sebaceous gland near the base of its tail.
