Well coming from the other side of things, I think most Jacks probably wouldn't do to well with young ones but I certainly can't say all. It depends on their temperment. We've currently got an intact jack that we specifically put out with our ewes at lambing because he is absolutely amazing with the lambs. If a lamb gets lost he will babysit it till somebody finds it, he'll help us bring the ewes into the lambing jugs and he always goes and greets the new lambs. He loves the little ones. As far as I know he's never tried to hurt or mount the ewes but we do have several jennys around for him to play with. Now, he is getting on in years so I don't know if that would have anything to do with it. Good luck with looking for one!