Cornish fowl vs poultry

Cornish fowl and poultry both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cornish fowl	Yes	No	No	No
poultry	Yes	No	No	No

As nouns, poultry is a hypernym of Cornish fowl; that is, poultry is a word with a broader meaning than Cornish fowl:

Cornish fowl: English breed of compact domestic fowl; raised primarily to crossbreed to produce roasters
poultry: a domesticated gallinaceous bird thought to be descended from the red jungle fowl

Other hypernyms of Cornish fowl include domestic fowl, fowl.

Cornish fowl (noun)	poultry (noun)
English breed of compact domestic fowl; raised primarily to crossbreed to produce roasters	a domesticated gallinaceous bird thought to be descended from the red jungle fowl
	flesh of chickens or turkeys or ducks or geese raised for food