Hank is seriously in problems. He flatulates on command. Doesn't matter what we feed him. He stinks. We have commiserated with other Rottie owners about the farts. Seems like they are not just powerful physically but also with their gifts from their back end.He really should not be having any gas. I would try to pick one protein for now and stick with it. If he does not like chicken then try beef or fish. Mine only get gas when they eat a pizza crust as a treat. I would try to stick to a simpler diet (he does not need such a variety) and maybe add a spoonful of plain yogurt to a meal once a day or give him a probiotic. If he is having gas...it means things are not digesting well.