pigeon breast vs chicken breast

pigeon breast and chicken breast both are nouns.

Word	Noun	Adjective	Verb	Adverb
pigeon breast	Yes	No	No	No
chicken breast	Yes	No	No	No

As nouns, pigeon breast and chicken breast are synonyms defined as:

pigeon breast and chicken breast: abnormal protrusion of the breastbone caused by rickets

pigeon breast (noun)	chicken breast (noun)
abnormal protrusion of the breastbone caused by rickets	abnormal protrusion of the breastbone caused by rickets