The wattles and combs are thick with capillaries and veins for the over-heated blood to pass through so the blood is air-cooled when it passes through these blood vessels. This process reduces the internal temperature of chickens, which is critical for them because they don’t sweat.
Wattles and wombs also indicate sexual maturity of chickens. Combs appear before wattles at the age of three weeks. Hen’s comb reddens when she starts laying eggs. For the roosters, larger wattles and combs attract the hens for mating.
A bright colored comb indicates good health. Discoloration, paleness, and blemishes indicate that the chicken is not feeling well.