I have a 3 month old male and he has been to the vet and stool tested, he's perfectly healthy. Just within the last 3 days he has had runny stool. He's still acting normal, eating and drinking fine and he's not excessively going, but this has me worried. The only thing new I have given him was a chew bone. Could this be the problem? I am a new puppy owner and I tend to worry a lot.