A turkey has several flaps of loose skin around the head and neck that turn color depending on its mood. The flaps are called the "wattle" (on the chin), the "snood" (on the head and over the beak) and the "caruncle" (on the throat). Under calm conditions, these areas are pinkish-gray or blue; if the turkey is annoyed or mating, all these areas turn bright red.
(Why don't humans have this capability. It would make life much easier.)