Feather
Young birds have small feathers, called down, which keep them warm, but cannot be used for flying.  Down is very soft.  Adult birds have down, but also have vaned feathers on top of the down. Down is also used in blankets. Down feathers are just one example of plumaceous feathers (the word means 'fluffy'). Another example is the feathers on flightless birds such as the ostrich.