Down Feathers

The Down of birds is a layer of fine feathers found under the tougher exterior feathers. Baby birds are clad only in down for instance, with the outer feathers growing after hatching.

It is a very good thermal insulator and has been used in insulating and padding jackets historically and ongoing. Some types of birds are well known for their down. Goose and duck down are well known for their warmth.

As it is a natural product often down can contain some of the outer feathers as the separation of down fathers and outers feather is never exact.