Many times coccidea won't show up on the fecal float..I hear it's one out of ten it might show up. I don't think it would hurt them to give them Albon for a week or two to see if things clear up. Also accidophillus (sp?) capsules sprinkled onto wet food may go down easier than yogurt. Same beneficial ingrediant. Does your vet carry Amphorol by chance? I had a litter of kittens some years back that had non-stop horrible diarrhea, and they'd had every wormer/protozoan treatment etc. out there. The only thing that finally cleared it up for them was Amphorol! Three times a day X three days, and they had formed stools. Poor sore little tushes..give the babies kisses for me (on the head)!