When you breed them you can hold a sword and hold e on them it gives you the option to slaughter. This kills them and you can just harvest them from there.
You should use Ovis for a mutton farm because mutton is like a less effective type of kibble. Most dinos Love mutton so this is a very useful way to use these!
If you wanna get wool without having to get ovis by just geting vegie cake make a cage with dino gate then get a argy to transport it into the cage then just simply shear it with scissors.