Down can be collected in a variety of ways. Birds which provide the feathers may be used for other purposes, for example to provide meat. Some birds are killed solely for their down, while some birds (particularly some geese) are periodically live-plucked of their breast feathers. Some birds, such as the eider duck, line their nests with down, and such down might be harvested safely after the young leave the nest.
Animal welfare groups consider the collection of down to be a painful procedure and cruel, particularly since birds must undergo down collection repeatedly.
The word down comes ultimately from Old Norse dúnn and is unrelated to the fact that down is found closer to the bird's skin than larger feathers.
Recent research suggests some dinosaurs may have had primitive, down-like feathers.