As Dr Williams said it is unlikely for a ferret to poop out a worm. To
answer the second part of your question- Yes you can use Interceptor (the
0-10 pound dog version) for your ferrets. Mine will actually eat the beef
flavored tablet by themselves, but I use for heartworm prevention (not as
a dewormer).
Jerry Murray, DVM
[Posted in FML issue 3406]