I remember this movie! In the end he gets sliced and diced by the propeller on a plane. Then sheep have a taffy pull with his hoo ha and end up biting it off!
That was something I asked myself when it was a Werewolf, as well as their insatiable hunger, even after eating someone. What I gathered recently, the Werewolf violence is due that the transformation keeps them in constant pain, hence their aggression. As their hunger, apparently they burn out/digest what they eat extremely fast, hence they continuously hunt, kill and eat till they revert hack to human. So a Weresheep would also be in constant pain and suffering, and as such would also be violent, crazed with their suffering.
I remember watching this with my dad at the end in the credits it said somewhere produced by new Zealand or something like that first thing my dad said was that explains the sheep shagging scene