There is probably no other breed of dog known better for being able to clear a room in less time just by doing what comes natural. Sometimes lovingly referred to as kibble fermentation vats, or walking stink bombs, bulldogs are proficient, to say the least, in the production of intestinal gas, or flatus. Flatulence can be a sign of food intolerances or insufficient intestinal absorption, most of the time, it is usually harmless, yet offending.
If your Bulldog seems to have an unusual amount of gas, have your vet check that there is not an underlying health problem, but most of the time the solution can be found by switching to a rice or wheat based kibble, or switching from canned food to dry food which requires more chewing so less air is being swallowed.