We had the same result with our current boxer with any of the Merrick foods. We ran out while traveling and tried to wean \ switch her to Merrick wet \ dry combo from NutriSource a couple times in her life and every time she starts throwing up like a cat or has diarrhea. Had 2 other boxers before and had nothing but success with Nutrisource with them and current boxer is the same its been a 10\10 for us with dog food in general. https://www.amazon.com/gp/product/B007L5DMXY
Raised platform like the neater feeder + legs is also a must if you dont already have one. https://www.amazon.com/Neater-Feeder-Deluxe-Bronze-Brands/dp/B002A2QUAA https://www.amazon.com/Neater-Feeder-Extension-Large-Bronze/dp/B002LKIC9S