In my experience, flatulence is a part of puppyhood. Winston had the smelliest farts ever when he was a pup, thank god as he aged that went away. Changing the food to one with a lower protein level might help to lessen the frequency. Nutro recently revamped their recipe and I've heard good things about it. Stick with chicken in whichever food you go to, as it is easier to digest.
"He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion."