With the hay shortage we're experiencing this winter, it's especially important to keep hay bales away from moisture to prevent nutrient loss and spoilage. Bales soak up moisture from ice, snow and rain, and when the water drains, the nutrients also escape. An average hay bale loses about one-fourth of its original nutrients during winter storage, but the loss can be reduced to 10 or 15 percent. Moisture also causes hay to spoil.
Location is another factor.
Bales set along the north sides of buildings dry slowly, and bales set in east-west rows get snow drifted on their south sides. As snow melts, it soaks into bales and makes the ground muddy. Crushed rock, railroad ties or pallets also keep the bottoms drier and make the bales easier to transport.