animal group vs brood

animal group and brood both are nouns.

Word	Noun	Adjective	Verb	Adverb
animal group	Yes	No	No	No
brood	Yes	No	Yes	No

As nouns, brood is a hyponym of animal group; that is, brood is a word with a more specific, narrower meaning than animal group:

Other hyponyms of animal group include team, flock, flock, fold, herd, herd, pack, pod, pride, clowder, school, shoal, caste, colony, warren, breed, stock, strain, drove, litter.

animal group (noun)	brood (noun)
a group of animals	the young of an animal cared for at one time

animal group (verb)	brood (verb)
	sit on (eggs)
	think moodily or anxiously about something
	be in a huff; be silent or sullen
	be in a huff and display one's displeasure
	hang over, as of something threatening, dark, or menacing