pinfeathered
Covered in quills
Pinfeathered describes a bird with pinfeathers—the immature, partially developed feathers still encased in their waxy sheaths.
A pinfeathered chick looks scruffy and incomplete, not yet having grown its full plumage.
The term extends figuratively to anything young, undeveloped, or not fully formed: a pinfeathered rookie, pinfeathered ideas.
fledgling
Inexperienced newcomer
juvenile · chick · pullet · cygnet · duckling · gosling · emerging · sprouting · budding · immature
poultry
Birds raised for food
barbs · coverts · preening · processing · dressing · singeing · scalding · pluckers · waterfowl · stubble