I suggest you give Blue Buffalo another try, but be sure to make the transition slowly. It is much more nutrient dense than the other two and your dogs need much less. I suspect that you overfed them on the BB. Calories per cup for fish and sweet potato are: 360 for Taste of the Wild, 394 for Natural Balance and 440 for Blue Buffalo. So a moderately active 100 lb dog would need about 1900 calories per day. That's 5 1/4 cups Taste of the Wild, 4 3/4 cup Natural Balance and and 4 1/4 cups Blue Buffalo. Gas and diarrhea are signs of over feeding.