The problem is that he had to castrate the Jacks because they will you know what. And, they will attack a sheep if they are lambing. Something in the blood gets them aggressive. Cattle on the other hand doesnt seem to bother them
The Jennys on the other hand are easier to handle and wont attack a ewe lambing.
Another thing is to keep any dog away from them if they are turned loose as a guardian. They’ll kill the family dog.