Interestingly enough, most of ours never fart....they are evidently satisfied with the occasional crap on the floor instead. It seems to be a game of sorts with them as we have three litter boxes and it isn't related to how clean they are. I think the little assholes do it just to piss me off. We have them ranging in age from almost 20 years to 4 months, 7 in all. Cutter, my old black kittup,in his last days; Genoa (Poogee)a calico, who is only affectionate when she's pregnant or nursing, the best Momma Cat I ever saw; Freddie Cougar, a blue/green eyed, champagne tabby, who sleeps 20 hours a day but also loves to nuzzle your neck; Gus, a sweet but bad-assed and fat-assed, long haired gray; Scrounger, my boy, and the name reflects his disposition, but also a great lap sitter, very doglike with me, follows me everywhere; Moggy, a gray & white Cornish Rex, suffering from terminal weirdness, but an outstanding lap cat; and Rocky, 4 months old and full of himself.Spaw