* How old are your ferrets? Ferret kits often need a bit more time to transition to dry food.
* What kind of dry food are you offering? Some ferrets are picky eaters, and some brands are more palatable than others.
* How long have they been refusing to eat dry food? This could help determine if there's a medical issue or if it's just a preference.
* What else have you tried? Have you tried mixing dry food with wet food? Have you tried different flavors or brands?
* Are they eating anything at all? If they're not eating any food, that's a serious concern and you should see a vet immediately.
Once you provide me with this information, I can give you more specific advice on how to help your ferrets eat dry food.