The main sources of protein in poultry rations are animal proteins such as fish meal, meat and bone meal, and plant proteins, such as soybean meal, cottonseed meal and corn gluten meal. The mineral portion of the feed is inorganic matter. Minerals, especially calcium and phosphorus, help build bones and make them strong and rigid. Laying hens also require minerals for eggshell formation. Other minerals are needed in trace amounts for all metabolic functions.
Grains are low in minerals, so it is necessary to provide supplements.
Calcium, phosphorus and salt are needed in the greatest amounts. Bone meal and defluorinated and dicalcium phosphates supply additional calcium and phosphorus. Ground limestone and oyster shell are good calcium sources. Trace levels of iodine, iron, manganese and zinc are also included in mineral supplements. Vitamins These substances occur in feeds in small amounts, but are absolutely necessary for growth, reproduction and the maintenance of health.