Since they've all been wormed, ask you vet if your money would be better spent looking for protozoas like blackhead, coccidia and giardia. Or maybe the money would be better spent checking the samples for infection. I'm not an expert, just sharing what I have learned and experienced with mine. So far, all of my fecals have come negative, but I'm pretty sure false negatives are a possibility... Talk to your vet, keep us posted.
-Kathy
-Kathy