Asked a former champion shearer, who said that maybe 1% of sheep being sheared get nicked, more likely by inexperienced shearers. If the skin is not held taut, nicks will happen. For people who shave their faces with a blade, how often do you nick yourself? Saying "half the sheep's skin" is a ludicrous claim. It's not like skinning mink - you want the animal to survive the process!