hen vs pullet

hen and pullet both are nouns.

Word	Noun	Adjective	Verb	Adverb
hen	Yes	No	No	No
pullet	Yes	No	No	No

As nouns, pullet is a hyponym of hen; that is, pullet is a word with a more specific, narrower meaning than hen:

Other hyponyms of hen include cackler, brood hen, broody, broody hen, setting hen, sitter, mother hen, layer.

hen (noun)	pullet (noun)
adult female chicken	young hen usually less than a year old
adult female bird	flesh of a medium-sized young chicken suitable for frying
female of certain aquatic animals e.g. octopus or lobster
flesh of an older chicken suitable for stewing