Boars must be sound to service sows. Compare the structure of the sound and unsound gilts in Figures 1 and 2. The gilt labeled unsound is straight in her shoulder, bucked over on her front legs, and steep and straight on her pasterns. She is also extremely high in her rump and post legged. Hogs of this type cannot stand the stress of breeding and farrowing, and also lack longevity(a long, productive life)