I'm gonna get same dog soon aswell.As for intoducing ferts to dog.All i did was watch her carefully and if she seemed a bit shady or curled a lip.I just gave a firm command "NO". was quite funny at times when the ferts gave a nip and the dog was lookin at me as if to say can i kill it lol..My ferts stopped nippin her and now she dont bother with them at all.Just remeber to watch them like a hawk until your totally confident they are bonded.A bite from a ferret on a dogs ear or whatever is no great deal.However a bite from a dog is a very dead ferret.Good luck and it will all come good.Get them