Morgan does this constantly too, and has ever since we got her. The only thing that stops her is to pick it up immediately. We've tried the suggestions offered in this thread, and nothing has worked. I hope something works for Kenny though, as it is absolutely disgusting.

I asked my vet about it and he said contrary to popular belief, it has nothing to do most of the time with something missing in their diet. It's just a natural habit they get into apparently.