What is the part on the chickens head called?

A cockscomb, cock's-comb, or (less commonly) coxcomb is a fleshy growth, caruncle, or crest on the top of the head of many gallinaceous birds, notably turkeys, pheasants, and domestic chickens. It is generally larger on males than on females.

The crest is a prominent feature exhibited by several bird and dinosaur species on their heads.