Abstract: A food product for animal consumption is prepared from an animal by-product, preferably a complete avian carcass. A heated hydrolyzing agent is applied by spray or dip coating to the carcass exterior. After initiation of hydrolysis, the carcass is ground, enhanced by additives, then steam heated to a temperature of about 200 degrees F. The heated by-product is provided as a slurry or as dry particulates to a twin screw extruder. As it is transported across several zones of the extruder, the by-product is thoroughly dispersively mixed and subjected to high pressures and temperatures, vented to release moisture, neutralized with a neutralizing agent, and blended under high temperatures and pressures sufficient to completely sterilize what has become a highly uniform and homogeneous by-product mass. The by-product mass is extruded and cut into pellets, which then are dried to a moisture content at or below 10 percent.