Just to throw my two cents in here, I use to feed Acana wild prairie, but had some issues with a couple of my cats, likely allergy related, the grasslands was ok, but too high in fat for my liking, lamb is suppose to be good for cats with allergies and easily digestible, but duck is high in fat. I was feeding Orijen until the price went up and the bag size shrunk a few months ago, so I've been feeding NutriSource for almost 2 months now. I have had a problem with one of my cats having horrible stinky poop, for years, like clear the room stinky, they were not loose just stinky. I always just assumed it had to do with her being an indoor/outdoor cat on an acreage, eating mice, birds, squirrels, etc. Since I switched foods to the NutriSource though the smell is pretty much gone, I mean it still smells like poop but like normal cat poop.
