Gallus gallus vs jungle fowl

Gallus gallus and jungle fowl both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gallus gallus	Yes	No	No	No
jungle fowl	Yes	No	No	No

As nouns, jungle fowl is a hypernym of Gallus gallus; that is, jungle fowl is a word with a broader meaning than Gallus gallus:

Gallus gallus: a jungle fowl of southeastern Asia that is considered ancestral to the domestic fowl
jungle fowl: small Asiatic wild bird; believed to be ancestral to domestic fowl

Other hypernyms of Gallus gallus include gallina.

Gallus gallus (noun)	jungle fowl (noun)
a jungle fowl of southeastern Asia that is considered ancestral to the domestic fowl	small Asiatic wild bird; believed to be ancestral to domestic fowl
a domestic fowl bred for flesh or eggs; believed to have been developed from the red jungle fowl