I give some cabbage my rabbits love it, I usually give one leaf of sweet york or savoy cabbage to Smokey and Bernie, and a half of that to my other rabbits. I don't give same vegetables every day so if it's once or twice a week I never had any troubles. If you'd give in large quantities maybe it cause gas indeed. If you are not sure you better don't or try to give a little and watch them or there are more vegetables than cabbages that they will love.