J.R.
Dairy, broccoli, melon and any whole wheat breads and pastas. A lot of fruits and vegetables cause gas but melons and cruciferous veggies like broccoli, cauliflower, brussels sprouts are the worst. Onion also causes gas so you could check any prepared foods you are using for onion powder. Watermelon and cantalope are big offenders. Try either eliminating one thing at a time or feed very bland for a few days, then add items back in one at a time. Chicken is probably the best meat to keep in while you experiment as fatty meats are more likely to cause gas, use white rice or potatoes and low gas fruits like apples (or applesauce), bananas, pears and low gas veggies like carrots, sweet potatoes.