Ingredients like grain, wheat, corn, and soy are known to cause tummy upset in dogs. (bestpets.co)
If not, consider sending his food to the kennel to prevent tummy upset from an abrupt diet change. (amcny.org)
You don't want to add too many fermented veggies to your puppy's diet at once as it could cause tummy upset, you also don't need a lot to be effective. (raisingrascal.com)