A healthy adult horse should eat 1.5% to 2% of its body weight in hay (or other forage) every 24 hours, measured on a dry matter basis. For a typical 1,100-pound horse, that works out to roughly 16.5 to 22 pounds of hay per day. This range covers most horses at maintenance, meaning they’re not pregnant, lactating, or in heavy work. The exact amount depends on your horse’s weight, workload, metabolism, and the quality of the hay itself.
Calculating Your Horse’s Daily Hay Needs
The math is straightforward: multiply your horse’s body weight by 0.015 and 0.02 to get the low and high ends of the range. A 900-pound horse needs 13.5 to 18 pounds. A 1,200-pound horse needs 18 to 24 pounds. These numbers assume you’re weighing the hay, not eyeballing it. A “flake” of hay can weigh anywhere from 2 to 8 pounds depending on how the bale was made, so flake counts are unreliable.
If you don’t have a livestock scale, a hanging luggage scale and a hay net will get you close enough. Weigh a few nets of hay to calibrate your eye, then spot-check weekly. Most people significantly overestimate or underestimate how much they’re actually feeding once they start weighing.
One detail worth noting: these percentages refer to dry matter weight. Most hay is about 85% to 90% dry matter, so the difference between “as fed” and “dry matter” is small, usually a pound or two. If your hay has been rained on or feels damp, you may need to feed slightly more to hit the same nutritional target.
Why the Minimum Matters
Horses produce stomach acid continuously, not just when they eat. In the wild, they graze 14 to 17 hours a day, and that near-constant chewing produces a steady flow of saliva that neutralizes acid. When a horse goes hours without forage, acid pools in the stomach and splashes into the upper, unprotected lining. This is the primary driver of gastric ulcers, which affect a surprisingly high percentage of stalled horses.
The Merck Veterinary Manual recommends never dropping below 1.25% of body weight in forage per day, and even that level calls for veterinary monitoring. Going below 1% of body weight, or fasting a horse for 24 hours or more, raises the risk of hyperlipemia, a dangerous buildup of fat in the bloodstream. Ponies, donkeys, and severely obese horses are especially vulnerable.
Horses That Need More
The 1.5% to 2% guideline is a starting point for horses at maintenance. Several situations push requirements higher.
Lactating mares have some of the highest energy demands of any horse. A 1,200-pound mare in peak lactation typically needs 10 to 12 pounds of good quality hay plus 12 to 15 pounds of grain mix to meet her calorie needs. Mares will naturally increase their intake during lactation and prefer to get as much energy as possible from forage rather than concentrates, which is better for their digestive health.
Growing horses, hard-working sport horses, and horses in cold climates also need more total feed. The National Research Council’s intake estimates for adult horses range from 1.5% all the way up to 3% of body weight depending on workload, with moderate work falling around 2% to 2.5%. In cold weather, hay digestion itself generates internal heat through fermentation in the hindgut, so increasing hay is more effective than increasing grain for keeping a horse warm overnight.
Horses That Need Less (Carefully)
Overweight horses and those with equine metabolic syndrome need calorie restriction, but cutting hay too aggressively creates serious health risks. UC Davis veterinary guidelines recommend starting these horses at 1.5% of their ideal body weight in forage per day, not their current weight. After 30 days, this can be lowered to 1.25% if needed. Sudden restriction should be avoided because it can spike blood fat levels and worsen insulin resistance.
For metabolically challenged horses, hay quality matters as much as quantity. The sugar and starch content of the hay, measured as non-structural carbohydrates, should be below 10% of dry matter. Soaking hay in cold water for 30 to 60 minutes can leach out some of these sugars, though results vary by hay type. Testing your hay through an equine nutrition lab is the only way to know its actual sugar content.
How You Feed Matters Too
Dumping an entire day’s hay ration in a pile invites a horse to eat it in a few hours and then stand with an empty stomach for the rest of the day. Horses chew long-stem hay at a rate of about 56 minutes per kilogram, producing roughly 4,050 chews per kilogram. That extended chewing time generates the saliva that buffers stomach acid, and it also satisfies the horse’s strong behavioral drive to forage. When that drive goes unmet, horses develop stereotypic behaviors like cribbing and wood chewing.
Small-hole hay nets are one of the simplest tools for stretching feeding time. A review of studies on slow feeders found they extend eating time by about 40% depending on mesh size and forage type. Some studies also found that horses fed from nets lost 20 to 23 kg over the study period while floor-fed horses gained weight on the same amount of hay. Splitting the daily ration across three or four nets placed around the stall or paddock mimics a more natural grazing pattern and keeps forage in front of the horse for more hours of the day.
Quick Reference by Body Weight
- 800-pound horse or large pony: 12 to 16 pounds of hay per day
- 1,000-pound horse: 15 to 20 pounds per day
- 1,100-pound horse: 16.5 to 22 pounds per day
- 1,200-pound horse: 18 to 24 pounds per day
- 1,400-pound warmblood or draft cross: 21 to 28 pounds per day
These ranges assume hay is the primary forage source and the horse is at a healthy weight doing light to moderate work. If your horse also has pasture access, the grass counts toward total forage intake, though estimating how much a horse actually eats on pasture is notoriously difficult. Horses on full-time quality pasture in the growing season may need little or no supplemental hay, while winter pasture provides almost none of their requirements.