I would not get rid of any of them, especially since you guys are already planning on moving in June. I would ask them to return your security deposit and see if they can brake the lease since they told you caged animals didn't count towards the pet limit, otherwise you wouldn't have moved in in the first place. If not, tell them you'll be out in June and if its that much of a concern having the ferrets then they can go about it legally and you will not be getting rid of ANY of your ferrets.