Table scraps, milk, starch products (Corn, potato, wheat, barley), Or even the ingredients in a dog's food will make them gassy. I've also noticed as my Dane ages, he has more gas. If your Pit is getting into it's older years, this may be a possibility. My Chihuahua, Chico, also got terrible gas when she was older. Stunk up the whole house, too. I suppose it depends on age, digestive needs, and their diet.