Hay Storage and Loss Prevention

Why does stored hay go bad?

Moisture is the main enemy. Rain, snow melt, groundwater and humid air all soak into bales, and wet hay grows mold, loses nutrients and can overheat. Sun bleaches the outside layers, and rodents, birds and insects add to the damage. Even the most carefully baled hay deteriorates if the storage plan is poor.

Losses are often invisible until you open a bale. The outer layer may be spoiled while the inside looks fine, or the bottom of a stack may be rotten while the top is good. Plan so that losses stay small and you can see them coming.

Different bale types shed water differently, and different regions face different moisture problems. Ask your county extension office how hay stores in your climate.

Where should I put the hay?

Choose ground that drains well and sits above the surrounding land, with no pooling water after rain. Keep stacks away from trees that drip, from roof runoff and from low spots. Leave space between rows so air can move and so you can reach bales with equipment without crushing them.

Think about fire as you pick the site. Stored hay is a fire hazard, and a barn fire can destroy animals, equipment and the building at once. Keep hay at a safe distance from homes, shops, fuel and main barns where you can, and ask your local fire department what they recommend.

Insurance, local fire codes and county rules may also affect how and where hay can be stored. If you are unsure, call your county office or insurer and ask before building a new stack near a structure.

• Well drained, slightly raised ground.
• Space between rows for air movement.
• Distance from buildings and fuel where possible.
• Easy access for equipment in any weather.

What keeps hay off the ground?

Bales that sit directly on soil wick up moisture from below. Pallets, gravel pads, old rails or a compacted base reduce contact with wet ground. Even a thin layer of gravel can improve drainage and help bales dry after a storm.

Keep the bottom layer in mind when you feed. If it is the layer you use last, it may be the layer that spoils first. Rotate stock so that older hay is used first and nothing sits for years.

How do covers, barns and tarps compare?

Indoor storage in a barn or shed gives the best protection but costs the most and carries the most fire concentration. Covered but open-sided storage protects well in many climates. Tarps can work if they are secured, sloped to shed water and replaced before they fail, though trapped moisture beneath a tarp can cause its own problems. Outdoor storage without cover leaves the most hay damaged.

Compare the cost of better storage with the cost of the hay you lose each year. If you lose a significant share, even simple cover may pay for itself within a few seasons.

How do I stack hay and handle moisture at baling?

Hay baled too wet can heat in the stack, and heat can lead to spontaneous combustion. If you make your own hay, ask your extension office how to check moisture before baling. If you buy hay, ask the seller about it and check bales for warmth and smell. If a stack feels hot or smells scorched, do not push into it alone. Call the fire department.

Stack to let moisture escape rather than trapping it, with tight, level stacks that shed water. Your extension office can tell you what works for the bale types common in your area.

Large round bales, small squares and other types each behave differently when stored. Round bales stored outside often lose a lot from the outside in, so how tightly they were baled and how they sit on the ground matter. Ask your extension office about options for the bales you use.

How do I protect hay from rodents and pests?

Mice and rats nest in hay and spoil it. Clean up spilled feed, keep grass and brush trimmed around stacks and consider traps or barn cats where appropriate. Avoid poisons where pets, livestock or wildlife can reach them, and check the label and local guidance first.

Bird droppings and wildlife contamination can also be a problem, so check the outside layers and discard anything soiled.

How can I measure and reduce my losses?

Weigh a few bales before storage and after, or note how many bales you discard at feeding. Even a rough count tells you which stack, cover or location performs best. Over a few seasons, you will see which changes pay off.

Ask experienced neighbors how they store hay in your local weather. Keep records and adjust, because every site has its own quirks.

• Record bales stored and bales wasted by stack.
• Compare cover types across seasons.
• Use older hay first and track the date it was cut.

Last reviewed: November 12, 2026. Written by the Rural Farm Life Editorial Team. See our editorial policy.