genus Gallus vs bird genus

genus Gallus and bird genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Gallus	Yes	No	No	No
bird genus	Yes	No	No	No

As nouns, bird genus is a hypernym of genus Gallus; that is, bird genus is a word with a broader meaning than genus Gallus:

genus Gallus (noun)	bird genus (noun)
common domestic birds and related forms	a genus of birds