Can't claim to be an expert.
Currently feeding 2 horses
4 y.o. gelding 1000#-1100#-- he has proven to be pretty efficient. When we first got him he was under weight by about 150#.
10 y.o. gelding 850#-950#-- got him in November, previously a rescue, only gelded at 9 y.o., turning out to be pretty efficient, easy keeper, but he can not tolerate straight sweet feed. He will get the skids if fed straight sweet feed.
I feed both horses pretty much the same ration measured by volume. 2 quarts feed (each) AM and PM containing 2 parts 12% All Brand sweet feed ($6.49/50#)and 1 part Strategy9$13.95/50#). The 4 y.o. gets about 1-1/2 flakes of hay and the 10 y.o. gets 1 flake. Both horses are stabled at night (1700), but turned out at 0600. We still have a slight amount of green in the pasture plus I keep a large round bale in the pasture. Total expendature of feed is about 200# a month.
Both horses are in pretty good shape, a little bit slimmer than they both were in Nov. but I think some of the weight loss is due to the change in housing. Both horse were solitary prior to Nov. Now that they are together they get more exercise. Ranger was stabled now on daylight turnout.