One must be careful what kind of wood pellets they are. There are litter products that consist of wood "pellets", but they are not the same as the kind I think you mean which are used for pellet stoves. Those may be okay, but the wood-pellet products that are specifically sold for animal litters are not suitable for ferrets. They contain too much pine resin, which is sticky and leads to the litter being tracked all over, and more to the point: the volatiles in the sap can be irritating to a ferret's nasal passages and even lead to illness. I tried some once and one time was enough for me. One day, actually. I still have the nearly-full bag. Stove pellets (if that's what you mean) are dried and more compressed, so I would think they would present fewer problems for ferrets. But let's be careful and specify what kind we mean. [Posted in FML 7406]