Squishypuff wrote:
I don't know how it could be worms though... we did the whole power pack thing, and I worm on time, religiously. I guess I'll try it again.

Worms continuously become immune to the dewormers, have you used Quest horse wormer? It's supposed to be effective when rotated with other wormers. Also to be sure, you might want to take a sample of his droppings to the vet & have them check it. It's not very expensive & will tell you for sure if your wormer is doing it's job.