I'm having trouble with my new ferrets, can I have some help?

Being owned by a ferret myself, my carpet shark was just always a little feisty. They each have their own personality. You need to keep at it and handle them both as often as possible. Age doesn't matter. You need to contact a vet in your area that deals with exotics or "pocket pets" and explain your questions to them. Understand that they are just playing and biting is a way of playing for them. We had purchased a product from our local pet store that contained apple bitter and it worked on my carpet shark. Its not expensive and you just spray it on whatever you don't want them to nip or bite at...just be careful to always wash your hands after using it, is does not taste good. Good luck!