 There is the physical suffering of tail-docking, de-beaking, de-horning, and castrating, all without anesthetic. Also, industrial farms make animals suffer psychologically by crowding them and by depriving them of interesting environments. Animals are bred to grow quickly on minimal food. Various poultry industry sources acknowledge that this selective breeding has led to a significant percentage of meat birds walking with painful impairments (see the extensive citations in HSUS 2009).