I’ve had a couple dogs have yellow stools. My current dog with food issues had nasty yellow mucousy bloody stools when I got him. My vet said he was sure he had IBS at 9 weeks old and that by 1 year he would prove to have IBD. Fortunately, the first things I tried for him got him on the right path and we have had no further problems with him as long as we stay on top of his food issues.
The other one had a protozoal infection that my vet made a guess at which antibiotics to try before we got results back from the lab, and fortunately, by the time we knew what we were dealing with, we already had a good handle on it.
