The feathers on a fledgling are commonly referred to as "down" feathers and "juvenile" feathers. Down feathers are soft and fluffy, providing insulation, while juvenile feathers are more developed and resemble the adult plumage but are not fully grown. As fledglings mature, they will gradually replace these feathers with their adult feathers through molting.
to have your chin tickled when you are unaware of it.
The feathers on top of a peacock's head are called a "head crest"
owlet feathers
Turkey feathers.
they are called Down Feathers.
contour feathers
Down
Most baby birds are born with feathers called 'down'.
Down feathers.
Disease - birds do not normally loose their feathers. When they change them it is called moult. Moulting is a process (like shedding in mammals) done regularly by birds, to replace old feathers with new, healthy feathers. This is normal. When a bird loses many feathers at once, it is usually due to the bird plucking out its own feathers OR a condition called French Moult, for which there is no cure.
tips of the main feathers
The feather is called a beard