The yolk color depends on the diet of the hen. If the hen gets plenty of yellow orange plant pigments known as xanthophylls, they will be deposited into the yolk. Hens that are fed mashes containing yellow corn and alfalfa meal lay eggs with medium yellow yolks, while those eating wheat or barley yield lighter-color yolks. A colorless diet, such as white cornmeal, produces almost colorless yolks. Natural yellow-orange substances such as marigold petals maybe added to light-colored feeds to enhance yolk color. Artificial color additives are not permitted.