The math isn’t terribly hard to do if you think in terms of pounds per day of hay fed subtracted out of a bale weighing X amount (approximate). Here on the west coast that’s pretty easy, as our bales of “east side” hay generally run 100lbs + per bale for normal 2 string bales. Easy to scale down to the smaller 50-60lb bales. So if one horse is fed 20lbs of hay per day, a small bale would last roughly 3 days. You’d need at least 2 bales per week. Then multiply by months needed. I do that for my two geldings who eat 20lbs. per day, every day, all year, though I have 110lb bales in right now.
I put my year’s worth of hay in the barn each August. I’ve happily fed 2 year old hay with no repercussions. I live in the very damp PNW-- but it’s a very different damp than the coastal SE. We don’t get your humidity levels! As others have said, the outside edges of some bales will get a bit “moldy” but that’s not a problem overall. I firmly believe in buying the best quality hay I can find as it cuts down on waste and leads to healthier horses, especially since pasture is limited here due to wet and in my case, size of farm.
I will say, “export” hay from the PNW will be in short supply this year, so heads up if you rely on it. Lots of hay ground was converted to hemp and weather conditions also left some farmers with only 2 cuttings instead of 3 for orchard and timothy. My hay supplier warned us all…
