sitter vs brood hen

sitter and brood hen both are nouns.

Word	Noun	Adjective	Verb	Adverb
sitter	Yes	No	No	No
brood hen	Yes	No	No	No

As nouns, sitter and brood hen are synonyms defined as:

Other synonyms of sitter include broody, broody hen, setting hen.

sitter (noun)	brood hen (noun)
a domestic hen ready to brood	a domestic hen ready to brood
a person engaged to care for children when the parents are not home
an organism (person or animal) that sits
a person who poses for a painter or sculptor