So, for deworming our horses, we give dewormer paste at regular intervals, rotating through the year. A couple weeks ago, as usual, we gave both of our horses the dewormer. Five days later, I saw the actual worms in Charlie's poo, two live pinworms. The vet came and suggested we get a fecal exam done. We got our results for that today-- and it was negative! So they're saying there are no worms. Is it possible for the worms to just die out?? Or am I missing something? I will talk to my vet as soon as I can, but I'm just looking for some other advice/opinions.?