Grass is Mother Nature at her best. It has everything that a horse needs. If they are being worked hard, a little grain will help with the energy but its like icing on a cake. It's the hay that provides the warmth. It's not the protein in it, it's the fiber in it. The horse's gut has to work harder and longer to digest hay and that is what produces the heat, plus it takes them longer to eat it than oats, and the effects of it will still be producing heat thru the wee hours of the winter mornings. I don't feed sweet feeds. If your hay is tested out of whack, then the sweet feeds don't improve it, just magnify the punch of being out of whack, it doesn't help to improve the balance at all. I always chuckle when I read the numbers on a feed tag and how its balanced to 1/5to1. Great. I guess I won't be making my out of balanced hay any worse with it. Now they are adding food grade medications into the feed bags, so I stopped laughing. I certainly wouldn't be buying feed with medications in it that my horse doesn't need...like biotin for example. A horse needs 5000mg of biotin a day and it does help build a hoof, but not remarkably so, and just go off it and see what happens.....stuck for life kind of thing....no thanks. I got off the sweet feed when my horse colicked badly and wrapped herself around a fence post and I had to haul her off of it. Went back to the bag and it smelled like beer....never again. My horse could have had lifelong disabilities from this episode and all I got from the feed store after I hauled the bad bag back was..oh, we're sorry, would you like a replacement?....nooooo thanks. At this time, I also got off the corn and switched to a 1/4 cup of oil a day and lost that silly explosive energy like a sugar high and got a more steady, sane and longer lasting ability to work instead....oh and the shine! Even my horse's old eye injury improved the lining around her eye and its not dry and crusty and needing so much attention anymore. Hope this information helps!