Poultry feed is food for chickens, ducks, geese and other domestic birds. Historically, poultry were mostly kept on general farms, and foraged for much of their feed, eating insects, grain spilled by cattle and horses, and plants around the farm. This was often supplemented by grain, household scraps, garden waste and some supplements.
As farming became more sophisticated and specialized, many farms kept flocks too large to be fed in this way, and nutritionally complete poultry feed was developed. Modern feeds for poultry consists largely of grain, protein supplements such as soybean oil meal, mineral supplements, and vitamin supplements. The quantity of feed, and the nutritional requirements of the feed, depend on the weight and age of the poultry, their rate of growth, their rate of egg production, weather factors (cold or wet weather causes higher energy expenditure), and the amount of nutrition the poultry unit obtains from foraging. This results in a wide variety of poultry feed types and the substitution of low cost local ingredients introduces more variations.