hen vs Gallus gallus

hen and Gallus gallus both are nouns.

Word	Noun	Adjective	Verb	Adverb
hen	Yes	No	No	No
Gallus gallus	Yes	No	No	No

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

hen: adult female chicken
Gallus gallus: a domestic fowl bred for flesh or eggs; believed to have been developed from the red jungle fowl

Other hypernyms of hen include chicken.

hen (noun)	Gallus gallus (noun)
adult female chicken	a jungle fowl of southeastern Asia that is considered ancestral to the domestic fowl
adult female bird	a domestic fowl bred for flesh or eggs; believed to have been developed from the red jungle fowl
female of certain aquatic animals e.g. octopus or lobster
flesh of an older chicken suitable for stewing