Desirable breeding stock must be structurally sound They need a sloping shoulder, forearm, and pastern to serve as front shock absorbers. A level rump, high tail setting, and hock angulation are also important, and there also must be a spring, or flexion(proper set to hock joint) for rear leg sound- ness. In addition, a level top, moderate length of neck, and large, even-sized toes aid structural soundness. Breeding swine need to move soundly and freely on pasture, or in confinement. Sows must be able to get up and down in far rowing crates. Boars must be sound to service sows.