Written by Rocky Mountain Metal · Reviewed by Micah Hostetler, Owner · Based in Penrose, CO, serving Colorado.
Store hay under a roof, off the ground, with air moving around the stack, away from animals and equipment. Moisture molds hay; hay baled too wet heats and can ignite. A ventilated steel hay barn handles both.
Key takeaways
- Roof on, ground off, air moving, in that order of importance.
- Hay baled too wet heats; watch new hay closely for the first several weeks.
- Store hay away from horses and equipment, or separate it with its own walls and doors.
- Size the building for a full year's supply plus room for delivery.
- A steel frame won't add fuel to a fire, but the hay inside still burns, so separation still matters.
How do I keep moisture out?
- From above. A sound metal roof with enough overhang to keep blowing rain and snow off the outside bales. Snow retention or a wider eave on the storm side helps.
- From below. Never stack on bare dirt or concrete without an air gap. Use pallets or a well-drained gravel base with the bottom course on dunnage.
- From the sides. Open sides ventilate but expose the outer bales; solid walls protect but trap moisture. A common Colorado compromise is solid steel walls on the weather side and an open or vented lee side, with the stack set back from the opening.
- From within. Stack loosely enough for air to move, leave channels, and don't wrap a stack in a tarp inside a building; it sweats.
- From the roof itself. Bare steel roof panels can condense and drip on cold mornings. Ask about a condensation strategy when you plan the building. See how to stop condensation.
Southern Colorado is dry, which helps a great deal. Wind-driven snow is the bigger problem, especially on the plains.
Why does hay catch fire?
Hay baled with too much moisture keeps respiring and supports microbial activity that generates heat. In a tight stack that heat can't escape, and past a point the hay can ignite from the inside. Most hay fires happen in the first several weeks after baling. Practical rules:
- Buy or bale hay that's properly cured, and ask about moisture at baling.
- Stack new hay loosely with air channels and check it with a hay probe for the first few weeks. Rising, hot readings mean pull the stack apart, and call the fire department if it's very hot.
- Don't put fresh hay against an older stack.
Should hay share a building with horses or equipment?
Ideally not. A hay fire in the same building as stalls is the scenario every horse owner fears. Best practice is a separate hay building a safe distance from the barn; second best is a bay with its own walls and its own exterior doors. Tractors, ATVs and anything with fuel or a hot exhaust also belong away from the stack. If you keep a working supply in the horse barn, keep it small and refill from the hay barn.
How big should a hay building be?
Figure the bales you feed per year, the bale size and how high you can safely stack, then add room to drive in and unload. For small squares, a 12-foot-deep bay stacked 8 feet high holds a lot of hay per running foot, and a 24×36 or 30×40 open-front steel building covers a typical few-horse operation for a year. Round bales want taller walls and wider openings for the tractor. We work out the size from your tonnage and bale type at the site visit.
What should the building look like?
A good hay barn has tall sidewalls, wide openings, a gravel floor and walls only where you need them. Steel-framed buildings do this well: the frame is engineered for your site's snow and wind loads, and a lean-to can add equipment cover. Agricultural exemptions often apply on ag land, though the roof still has to carry the snow. See do I qualify for an ag exemption? and what snow load does my building need?
What layout details matter?
- Open side or large doors facing away from the prevailing wind.
- Drive-through, or at least drive-in, access for the delivery truck and your tractor.
- Lighting outside the stack area, never buried in it.
- No electrical panels or outlets in the hay area; keep wiring in conduit.
- A hydrant nearby.
How do I get a hay barn planned?
Rocky Mountain Metal sells steel-framed metal buildings only. We look at your site, size the building to your hay, and place the order with 1st Choice Metal Buildings and Carports. The manufacturer's crew from Texas installs it, and we oversee the project. See agricultural buildings and our service area, then request a free quote. Related: how big should a horse barn be?
Frequently asked questions
Can I store hay in my horse barn?
A small working supply, yes, with care. Main storage belongs in a separate building or a separated bay for safety and air quality.
Should a hay barn have walls?
Walls on the weather side and an open or vented lee side is a good Colorado compromise. Fully open buildings ventilate best but expose the outer bales; fully closed ones need deliberate ventilation.
How long does hay keep?
Well-cured hay stored dry keeps its feed value for a long time; it loses quality faster in sun, rain and on bare ground.
Does a hay barn need a permit?
It often qualifies for an ag exemption on agricultural land, and setbacks still apply. Requirements vary by county, and we'll walk you through yours. See do I need a permit?
