The Real Cost of Leaving Round Bales Uncovered

This is the article we wish a few of our customers had read three winters ago. Round-bale loss math doesn't show up on any invoice, which is why most operators underbudget for it. We've been delivering fabric buildings to Prairie hay producers since 2018, and the gap between what producers think they're losing in the yard and what the math actually says is consistently large. Below is the full breakdown — sources of loss, the per-bale dollar math, the building sizes that pencil out, and the alternatives that work and don't work.

What does "uncovered storage loss" actually mean?

It's not just the bales that look obviously rotten in spring. Total dry-matter loss on uncovered ground-stored bales runs 15–35% per storage season on the Prairies, depending on rainfall, snow cover, and how the bale was wrapped. The loss has three components, in rough order of how much they contribute:

• Ground contact (40–55% of total loss). The bottom of the bale wicks soil moisture, rots, and bonds to the ground. The bottom 4–8 inches becomes feed waste — often more if the bale sat in a depression that pooled water. This is the single largest source of loss in uncovered storage.
• Outer rind weathering (30–40%). The exposed top and sides develop a 4–6 inch weathered rind that's lower in protein, higher in mould, and less digestible. Cattle will pick around it given the choice.
• UV breakdown (10–20%). Sunlight degrades the surface protein and breaks down structural carbohydrates. The damage is nutritional rather than visible — you don't see it; you see it in winter feed intake going up.

Net-wrapped bales lose less than twine-tied bales. Bales stored on a slope and shedding water lose less than bales sitting in low-spot pooling. Bales stored in north-south rows lose less than east-west rows because the same side gets sun-cycled rather than alternating. None of these adjustments get loss below about 12% — only roof + pad does that.

What's the per-bale dollar number?

Round-bale weight varies from roughly 1,000 lb to 1,800 lb depending on diameter, density, and moisture. We'll use 1,400 lb (about 0.635 tonnes) as a working average for 5'×6' Prairie hay bales. At $250/tonne for grass/legume mix (current Alberta range as of April 2026), that's about $159 of feed value per bale at full quality.

At 25% loss — typical of uncovered ground storage on the Prairies — you're losing about $40/bale every storage season. On a 500-bale operation that's $20,000 of nominal feed value lost. Most of that you don't recover even if the bale "looks fine in spring," because intake and digestibility have both dropped on the surviving feed. The realistic effective loss-cost — feed disappeared plus extra bales fed to compensate for lower energy — runs $35–50/bale.

Cost per bale assumes 1,400 lb average bale at $250/tonne. Loss ranges reflect Alberta extension findings and our own customer reports.

How fast does a fabric building pay for itself?

Take the 500-bale operation at $250/tonne and compare uncovered (25% loss) to roofed (5% loss). The differential is 20 percentage points × 0.635 t/bale × 500 bales × $250/t = roughly $15,900/year saved feed value. A 40' × 60' fabric building delivered, anchored, and installed sits in the $20,000–$25,000 range as of April 2026 — full pricing on the homepage. The building pays for itself in 1.5–2 winters at this scale, and lasts 25+ years.

At 1,000 bales/year — common for medium cow-calf and dedicated hay operations — payback drops to under 12 months. At 100 bales/year — small acreage, a few horses — the payback math doesn't quite carry the cost on its own and the build is justified more by the equipment-storage and tractor-shelter co-uses. That's the threshold we use when a customer asks if it pencils for them: above ~150 bales/year on a hay-only basis, yes; below that, only if the building is doing two jobs.

What size building for what bale count?

Working numbers for 5'×6' round bales stacked three high on pallets or rails, with no interior tractor aisle:

• 30' × 60' (1,800 sqft): ~150 bales
• 40' × 60' (2,400 sqft): ~250 bales
• 40' × 80' (3,200 sqft): ~340 bales
• 50' × 100' (5,000 sqft): ~500 bales
• 60' × 120' (7,200 sqft): ~720 bales
• 70' × 150' (10,500 sqft): ~1,050 bales

Add 20% capacity if you can stack four high — peak height of 22–28 ft makes that possible with a telehandler. Subtract 15–20% if you need a tractor aisle through the middle for loading/unloading. Run your numbers in the cost calculator; it'll spit out the same prices we'd quote on the phone.

Does tarping work? When?

Tarping is genuinely useful and we don't dismiss it. Done properly, it cuts loss to 8–12%, which is meaningfully better than bare. The reasons tarping doesn't replace a building over a 10-year horizon:

1. Tarps are a labour line item every spring (re-anchor after Chinooks) and every fall (lay them on, every stack). On a 500-bale operation that's days of work each year.
2. Tarp lifespan in Prairie sun is 3–5 years on a heavy-grade tarp, 1–2 years on a light tarp. Replacement isn't free.
3. Mice, raccoons, and bears tear tarps. We've replaced more than one tarp on customer sites where wildlife had a productive winter.
4. Tarps don't stop ground-contact loss — they only address the rind. If you're not also moving bales onto a pad or pallets, you've fixed half the problem.

For 100–200-bale operations, a tarp on a gravel pad with proper anchoring is reasonable. Beyond that, a roof is cheaper per protected bale per year.

Other things we've watched go wrong in bale yards

A few patterns from delivery sites and customer follow-ups:

• Bales stacked tight against each other on the ground. Looks efficient, traps moisture between rounds, accelerates sidewall rot. Leave a foot of air gap or stack pyramid-style.
• Bales on the leeward side of a treeline. Snow drifts there. The drift melts onto the bale tops in March and freezes overnight, creating an ice cap that holds water against the bale through April.
• Bales stored under a yard light or mercury vapour fixture. Doesn't matter to the hay, but the lights attract moisture-loving wildlife (mice, voles, raccoons) that nest in stacks.
• Bales stored too close to a yard entrance. Diesel and dust get tracked into them by passing equipment. Cattle don't love it. Nothing rejects feed faster than diesel taste.

What we'd do on a typical 500-bale operation

If we were starting fresh: 40' × 80' fabric building on a 6-inch compacted gravel pad with a slight crown for drainage, helical anchors, sliding 14' end door for tractor access, ridge vent. Stack three high on used pallets. Run a row of older twine-wrapped bales on the outer perimeter as sacrificial wind/snow break for the higher-value net-wrapped feed in the centre. Winter hay storage in fabric buildings has the full layout if you want the longer treatment.

Where to read next

• Winter hay storage in fabric buildings — protecting your feed
• Hay storage solutions — keeping bales dry and mould-free
• The complete cost breakdown of owning a fabric storage building

Written by the MAX Storage Buildings team. Loss percentages reflect western Canadian extension data and our own customer self-reports across delivered installs. Hay-price figures are Alberta auction-mart Q1 2026 averages — pricing on our homepage is the live source for building costs; check there before confirming a quote.

Last updated: April 29, 2026