Methods for Determining the Nutritive Value of Feather Meals

RAW feathers and other scleroproteins are high in protein but they are poorly digested unless the raw products are rendered susceptible to enzymatic hydrolysis either by physical or chemical treatments (Davis et al., 1961). Raw feathers are steam cooked at various pressures and time periods in order to produce a digestible product. Properly hydrolyzed feathers contain approximately 85% crude protein of which 80% is digestible. This product is commonly referred to in the feed trade as hydrolyzed feather meal and is used as a source of protein in many mixed feeds. The quality of this product, for animal feeding, depends largely upon the efficiency of the hydrolytic process (Davis et al., 1961; Sullivan and Stephenson, 1957; Combs et al., 1959). A crude protein analysis does not distinguish between raw and hydrolyzed feathers and gives relatively little information about the quality of the product. A microscopic method (Brown and Fraps, 1944) …