offspring vs hatchling

offspring and hatchling both are nouns.

Word	Noun	Adjective	Verb	Adverb
offspring	Yes	No	No	No
hatchling	Yes	No	No	No

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

Other hyponyms of offspring include orphan, young mammal, young bird, spat, young fish.

offspring (noun)	hatchling (noun)
any immature animal	any recently hatched animal (especially birds)
something that comes into existence as a result
the immediate descendants of a person