What is the red part of a roosters head?
The red part of a chicken's head is called the comb.
That is called a comb and it has two functions. The first is to cool the bird down when it gets very hot in the summer. The blood flows into the comb and also the wattles. The blood then releases heat out through the comb. The other function is too attract a mate. The male has a larger comb and the red color announces that he is a male and old enough to breed.