Lately Lightning has been passing very stinky gas very often. He was never gassy before. Nothing has changed, except that I've started mixing a little Nutro Lamb and Rice in with his Nutro Lite, in an effort to curb his poop eating (which seems to have worked). He's just turned 8, he appears to be in excellent health. Is it just an age-related thing? He wolfs his food down, and I actually massage his tummy after he eats to make him burp (easier and cheaper than bloat surgery. I need to get one of those dog bowls that slows down their eating, if I can remember where I saw it.) Could that be causing his problem?