is that the amount you are putting back each month? or is that the amount you have to spend on feed each month ? I guess since you are in Idaho they have other types of hay then alfalfa? You dont state if your horse is on a pasture ( means there is grass/ lots of it) or in just a large pen dry lot, or stall ? If all you are feeding is hay , no pasture, depending on the size and density of the alfalfa bale , or grass hay , an average horse gets 10 -15 lbs of forage a meal. Depends on the horse. They need forage for their guts to properly work. If you are going to get a pellet or hay cube, that may work but is More costly. I purchased 44 tons of hay last august, just had to purchase 100 more bales (120lb bales dense hay bale last about 9 days per horse) I started off feeding 18, 3 were euthed, 4 are on pasture since April but still get a small , very small portion of hay per day, which will increase as the weather turns cold and pasture goes dormant.