Insoluble granite grit is not necessary in manufactured diets of commercial poultry. Additives often used in poultry diets include drugs, feed preservatives, and growth stimulants. Withdrawal feed is fed during the last 3-5 days and contains no restricted drugs or vitamins. Starter feeds are mash or crumbles while other broiler feeds are pelleted. Pullet and breeder feeds are fed as mash.
Remainder is made from animal meals, minerals, vitamins, drugs and fats.
Energy increases with age. Prescribed amounts of different feeds are delivered for feeding rather than feeding for various periods of time. Facilities with two feed bins allow complete use of one diet before switching to the next diet. Exercise precautions that insure the best quality feed for the birds. Proper adjustment of feeding system is essential for best feed efficiency.