Happy to hear is he doing well.
Pedigree probably did not cause the upset stomach because he has been eating it for so long, but a food change can help a GI pup.
BB is not the only option. IMO, it is a lot of money for this particular company.
Just a thought about feeding large dogs. My sister and BIL feed BB and hate spending money. lol. So they made a deal with a PetSmart manager to get it discounted if they buy x amount at once.