COMPOSITION OF POULTRY
29. The composition of poultry is very similar to that of meats. In fact, poultry is composed of protein, fat, water, mineral salts, and extractives that do not differ materially from those found in meats. The protein, which usually varies from 15 to 20 per cent., is a much more constant factor than the fat, which varies from 8 to 40 per cent. This variation, of course, makes the total food value high in some kinds of poultry and low in others. For instance, in a young broiler that has not been fattened, the food value is extremely low; whereas, in a mature well-fattened bird, such as a goose, which increases very markedly in fatty tissue after reaching maturity, it is extremely high. A factor that detracts considerably from the edible portion of poultry is the waste material, or refuse. This consists of the bones, cartilage, head, feet, and entrails, or inedible internal organs. The greater the proportion of such waste material, the more the total nutritive value of the flesh is reduced. It is claimed that birds that have light-colored flesh do not become so fat as those which have dark flesh. This, of course, makes their nutritive value less, because the fat of poultry is what serves to supply a large part of the nutrition. There is no particular difference, as is commonly supposed, between the red and white meat of poultry. The difference in color is due to a difference in the blood supply, but this does not affect the composition to any extent.