I would definately get him on a quality food -- not Purina Puppy Chow -- it is full of fiber and that is what give the poor thing all the gas. IT fills them up, they will grow but there are lots better choices out there. Check out one of the dog food comparison sites like
Dog Food Reviews - Main Index - Powered by ReviewPost
Since he is almost a year old now, it would be a great time to make the change. You can feed about half of his current Puppy Chow and half of a new quality Adult or All Life Stage food. Do that for a week, then do 3/4 new food and 1/4 old food for a week, then you can probably go ahead and switch all the way to the new food.
Some good choices: Wellness, Canidae, Chicken Soup, Merrick.....
Another nice side benefit to switching to a quality food, you will find their poops are much smaller, compact, and easy to clean up.