Some dogs really need to be on an intermediary food for a while before switching to high test. That being said, there have been some reports of quality issues with Merrick here and there, so you may have gotten a bad bag. You might want to try switching to a brand like NutriSource. It’s usually very well tolerated and easy to transition to, so it makes a good stepping stone food. Earthborn and Nature’s Variety, both, have premium and super premium foods, so they would be good steps up from what you were feeding.
