For "grain" I feed mine 1/2 scoop of Alfalfa pellets (3 qt scoop, about 1.5 lbs) with flax and Nutri-Plus
supplement. I use the flax because we do not have any grazing (hfresh grass has Omega 3's, but hay does not). You could skip that part and do just the hay pellets and supplement. It makes a well rounded diet without the sugar and starch! If you find any losing weight, you can increase the hay pellets. During the winter, feed plenty of grass hay and add in the flax.