I have a quarter horse that really needs to lose weight. I will cut back on hard feeds and hay, but once she has the grass down as she does now and don't want to move her to more grass yet as she will only get bigger, she digs up roots and ends up with sand in her belly. Already had colic surgery once don't want to do that again. I have heard of using straw as low calories and gives them something to munch on. What type, where do you get it, and do you give it ad lib. Also has anyone tried a muzzle to stop the constant foraging through the sand? Are there other low calorie feeds? Also soaking hay an option?