I have enough I think, and am cutting back at present on pm haying, as they are turned out to pasture and are just wasting it, so am only doing AM. Have talked about a complete feed, and about getting beet pulp, and alfalfa that is crushed too.
Horses I believe can get by with 1-2% of their body weight in roughage. Here is a link, and there are plenty of others too. http://www.pet-care-and-training.com/roughage.html
Straw many hesitate to feed for roughage though due to problems associated with it.
I was scrolling through CL and other places and the prices of horses has dropped tremendously already.