Gassiness, at least in our house, for my bully means that a certain food is not agreeing with him. For example, if I give him cauliflower, he will be gassy all night. When I was feeding him Orijen six fish, he was constantly gassy but once, I switch him over to something else, the gassiness stop. So definitely check his diet and see which is the culprit. I hope this help.
Agreeing with Susie, sounds diet related...even a bite or two of people food (pizza, cookie, etc)
could do it, store treats containing grain or certain protein that doesn't agree w/them. The Nutro
might be fine but the protein source might be wrong...for instance, are you feeding chicken Nutro,
then you might try lamb Nutro or Bison Nutro. Many bullies are sensitive to chicken...it makes Cami
have terrible gas! She is now on TOTW Bison & Venison and has no gas. If she gets pizza, cookies
or occasional bite of chicken...terrible, stinky gas!
Sorry...in trying to help, I went to your profile page where it still states you feed royal canin.