Hay calculator (winter feed planning)
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top — code ready, activates once AdSense is approvedThe calculation, step by step
At 2% of body weight, one 1,000 lb horse eats 20 lb of hay a day. Over a 150-day winter that is 3,000 lb — 60 square bales of 50 lb for a single horse, before any waste.
A worked example
Two horses averaging 1,000 lb, fed 150 days, at 2% of body weight, with 10% waste allowance, in 50 lb bales at $8:
inArticle — code ready, activates once AdSense is approvedWaste is not optional
Hay fed on the ground, in the rain, or from an open ring is wasted at rates from 5% to over 30%. Common findings from feeding trials:
| Method | Typical waste |
|---|---|
| Fed on the ground, outdoors | 20–30% |
| Open ring feeder | 10–20% |
| Covered feeder with a basket | 5–10% |
| Small-hole slow feeder | under 5% |
Upgrading the feeder usually pays for itself within one winter, and slow feeders also stretch eating time, which is good for the gut.
Cold weather changes the maths
For every degree below about 5 °C (41 °F), a horse’s energy requirement rises, and the increase becomes substantial in hard frost and wind. Feeding extra hay rather than extra grain is the safer response: the fermentation of fibre in the hindgut generates heat, which is exactly what a cold horse needs.
Rule of thumb: below freezing, add roughly 10–20% more hay. Add a bale or two to your order rather than being caught short — hay is heaviest and most expensive exactly when everyone runs out.
Frequently asked questions
How many bales of hay does a horse need for the winter?
At 2% of body weight, a 1,000 lb horse eats about 20 lb of hay a day, so a 150-day winter needs about 3,000 lb — roughly 60 bales of 50 lb, plus a waste allowance.
How much hay does a 1,000 lb horse eat per day?
About 15–20 lb per day for a horse at maintenance, depending on weather and body condition. It should be at least 1% of body weight, ideally closer to 2%.
How much hay waste should I allow for?
Budget 10% with a good covered feeder, 20–30% if hay is fed on the ground outdoors. Weighing what is left in the field is the only way to know your own figure.
Should I feed more hay or more grain in cold weather?
More hay. Digesting fibre generates body heat, so extra forage warms a horse as well as feeding it, whereas extra grain raises the risk of digestive upset.
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Sources and method
- Equine extension guidance on feeding 1.5–2.5% of body weight per day, with a minimum of roughly 1% as long-stem forage.
- Ontario Ministry of Agriculture, Food and Rural Affairs — Estimating body weight for horses (for the weight figure rations are based on).
Page last reviewed 2026-10-16. Results are estimates from published formulas and are not veterinary advice.