Since more is known about the nutritional requirements of the chicken than of any other domestic animal, it is not surprising that rations are scientifically balanced to assure layer health along with optimum quality eggs at least cost.
Because care and feeding of hens, maintenance, sanitation and egg gathering all take time and money, there is a strong trend toward automation whenever possible. Automatic feeders, activated by a time clock, move mash through troughs in the floor or past the cages. Birds at floor level drink from troughs. Those in cages may sip from such sophisticated accessories as self-cleaning drinking cups or nipple valves.
Most poultry rations are of the all-mash type. They are made of sorghum grains, corn, cottonseed meal or soybean oil meal depending upon the part of the country in which the ration is produced and which ingredient is most available. The feed is carefully balanced so that the hen gets just the right amounts of protein, fat, carbohydrates, vitamins and minerals.
Today's hen eats a better balanced diet than many people! The hen's ration may contain the same types of additives approved for human food. Antioxidant or mold inhibitors (also used in mayonnaise and bread) are added to maintain the quality of the feed. And, like people, chickens occasionally require an antibiotic. An additive is not approved for use in poultry feed unless adequate research has been undertaken to determine its pharmacological properties and possible toxicity and to discover any potentially harmful effects on animals. Hormones are not fed to poultry in the United States.
How much a hen eats depends upon the hen's size, the rate of egg production, temperature in the laying house and the energy level of the feed. In general, about 4 pounds of feed are required to produce a dozen eggs. A Leghorn chicken eats about 1/4 pound of feed per day. Brown-egg layers are slightly larger and require more food.
Egg quality is affected by the type feed. Shell strength, for example, is determined by the presence and amounts of vitamin D, calcium and other minerals in the feed. Too little vitamin A can result in blood spots. Yolk color is influenced by pigments in the feed. Maximum egg size requires an adequate amount of protein and essential fatty acids.