Domestic ducks belong to the genera Anas and Cairina. Most breeds descend from the mallard duck (Anas platyrhynchos), which was domesticated in southern China. They are a particularly important food source in rural areas of Asia, especially in Southeast Asia. The Muscovy duck (Cairina moschata) was domesticated in Latin America, where it remains ubiquitous. It is also found in all equatorial countries of Africa and Asia, especially in Southeast Asia. The Muscovy is an extremely good forager that does well under free-range conditions because it does not need much water.

Ducks have a number of advantages over other poultry species, in particular their disease tolerance. They are hardy, excellent foragers and easy to herd, particularly in wetlands, where they tend to flock together. A disadvantage of ducks, when kept in confinement and fed balanced rations, is their high feed wastage, due to the shovel-shape of their bills. This makes their feed use less efficient, which goes to explain why their meat and eggs are more expensive than those of chickens.

In countries where rice is grown in paddy fields, synergies may be found between duck and rice production. Extensively grazed domestic ducks act as natural predators against insects, slugs and snails and also feed on grain which would otherwise be lost during harvesting and winnowing. The role of ducks as predators and as producers of natural fertilizer – with the manure they leave on the rice fields – contributes to higher yields.