Cuticle and Color The hen’s finishing touch on her egg is a thin proteinaceous cuticle. This coating initially plugs up the pores to slow water loss and block the entry of bacteria, but gradually fractures to allow the chick to get enough oxygen. Along with the cuticle comes color, in the form of chemical relatives of hemoglobin. Egg color is determined by the hen’s genetic background, and has no relation to the egg’s taste or nutritional value. Leghorns lay very lightly pigmented “white” eggs