animal group vs breed

animal group and breed both are nouns.

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

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

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

animal group (noun)	breed (noun)
a group of animals	a special type
	a special variety of domesticated animals within a species

animal group (verb)	breed (verb)
	have young (animals) or reproduce (organisms)
	copulate with a female, used especially of horses
	cause to procreate (animals)
	call forth