The single comb shape is the most common variety of comb, and usually the most well known. It's characterized by a flat vertical base protruding from the top of the head, a varying number of spike-like points, and a blade. The single comb varies greatly in size from chicken to chicken and breed to breed, although rooster's combs are generally bigger. A healthy single comb is always red. Purple can signify frost-bite or other heath problems, while pink is much more common, and while it can be from health problems, hens that aren't laying eggs regularly often have pink, dry combs.