Stormchaser, as Mary Ellen said "Bloody diarrhea can be a symptom of coccidiosis, not uncommon in pups". The day we picked Toto up, we met the breeder at the vet's office and she brought all the littermates for their checkups and Toto was the only one who didn't check positive for coccidiosis! She was a tad over 16 weeks old and weighed 1 lb. 8 oz. When we got her home she wouldn't eat hardly any of the food brought by the breeder [frozen Bil Jac] so two days later as panicky "new parents" we took her back to the vet. She checked positive for coccidiosis
and had lost 3 oz! My husband and I were mortified!
She gave her antibiotic for 14 days and we haven't had a problem since. We take her at least once a month just to have "Dr. Lucy" look her over and make sure she is tip top!! Every time we take her we always take a stool sample just as a precaution.