[theBCnut]

It may not be an ingredient so much as how his digestion is working. Adding fiber doesn’t mask anything, it changes the way moisture is retained in the bowel and it helps the food pass at a more consistant rate. For dogs with hard stools, it helps keep them soft enough that they keep moving. And for dogs with soft stools, it slows them down enough that they have more time for the large intestine to do its work, which is to resorb nutrients and moisture. Try the fiber.