Tony, as ferretlove said over feed it and I always find that squirty cream on your palm works a treat. I have had a similar problem recently, I left my three ferrets with someone whilst I went on holiday, when I went they were like kittens ands were handled daily by me and my eldest daughter. When I returned they were nipping, this person has kept ferrets and was supposed to be confident with them, I think they were strangled and the gaunletts on my cage were proof of the incompetence. You live and learn........