tail feather vs quill

tail feather and quill both are nouns.

Word	Noun	Adjective	Verb	Adverb
tail feather	Yes	No	No	No
quill	Yes	No	No	No

As nouns, quill is a hypernym of tail feather; that is, quill is a word with a broader meaning than tail feather:

Other hypernyms of tail feather include flight feather, pinion, quill feather.

tail feather (noun)	quill (noun)
feather growing from the tail (uropygium) of a bird	a stiff hollow protective spine on a porcupine or hedgehog
	the hollow spine of a feather
	any of the larger wing or tail feathers of a bird
	pen made from a bird's feather