I have two castrated ferrets. Hobs will come into season even if there is no jill ferrets. I would go with castration as there is no hormones produced by the boy, your ferret will want to be your friend and become more playful too. You don't have to wait a year before your Hob can be castrated, mine were done after 6 months. The only downside is that your jill will need bringing out if season every year.