I've heard to NOT feed it until 18 to 24 months of age, because it has too much protein for a growing pup. You don't want them to grow too fast. Also my vet said too much protein in the diet for a puppy can also result in bloody stools because it can cause stomach and intestine irritation. He said he's seen it several times, and he'll run test for parasites and other things to make sure that's not the problem. If the tests come back negative then he'll ask what the pup is eating, and most of the time it's a diet high in protein. This happened to our rat terrier. We were feeding her Eukanuba when we first got her and she had blood in her stool. So he ran tests to make sure it wasn't a parasite or anything else, and he said Eukanuba had a high protein content, so we changed her to Canidae.