Hi Natalie-
I think that Amy W had a good suggestion with keeping notes. Get a journal and start documenting all of the times he has bad stool, good stool, anything and everything that is abnormal or even normal. I don’t know that we have been given enough information to help, but I can tell you that the one food that agrees with my dog who has stomach issues, food sensitivities etc is Purina Pro Plan Sensitive Skin & Stomach Salmon (they also have a lamb, which we don’t use). Maybe this is a food that could help him? It’s hard to say.
