Feeding Horses: Hay, Grain and Supplements

The horse is built to eat small amounts of forage almost all day. Good feeding starts with hay or pasture, adds concentrates only when the horse needs them and changes slowly. This guide explains the numbers and the choices.

Forage comes first

The National Research Council recommends that horses eat at least 1.5 percent of their body weight in forage each day, measured as dry matter, and many do best at about 2 percent when hay is the main feed. For a 1,000 pound horse, that is 15 to 20 pounds of hay a day. Forage keeps the gut moving, supplies fiber and calories and occupies the horse for many hours, which lowers the risk of ulcers, colic and stable vices. Do not cut forage below 1 percent of body weight even for a horse that needs to lose weight, and use a slow feeder or small-hole net to stretch it instead.

Calculating hay

Start with the horse's weight (see How to Estimate Your Horse's Weight), multiply by the percentage you want to feed and add an allowance for waste. Hay thrown on the ground, or fed from round bales without a feeder, can lose 10 to 30 percent. The Hay Calculator converts the daily figure into bales and shows how long a stack will last for your number of horses. Weigh a few flakes on a hanging scale, since flakes and bales vary a lot in weight.

Horse weight	1.5% of body weight	2% of body weight
800 lb	12 lb	16 lb
1,000 lb	15 lb	20 lb
1,200 lb	18 lb	24 lb

Choosing the hay

Grass hays such as timothy and orchardgrass are lower in calories and protein and suit most adult horses. Legume hays such as alfalfa are higher in protein, calcium and calories, which can suit growing horses, hard keepers, lactating mares and horses in heavy work. Mixed hays sit in between. Good hay smells fresh, is free of mold and dust, has leaves still attached and is not full of weeds. A hay analysis from a lab tells you the real protein, energy and sugar content, and it is the only way to match hay to a horse with metabolic problems. The Hay Finder narrows the choices from your horse's age, workload and condition.

When a horse needs concentrates

Many horses do well on forage plus a ration balancer, a small amount of concentrated vitamins, minerals and protein. Horses that need more calories, such as hard keepers, hard-working horses, seniors with poor teeth, and broodmares, may need a feed. Pick the feed from the horse's needs, not the label's pictures: low-starch feeds suit easy keepers and horses prone to metabolic problems, senior feeds suit older horses, and performance feeds suit horses in hard work. Feed by weight, not by scoop, and follow the amounts on the tag, since feeding less than the minimum means the horse does not get the vitamins and minerals listed. The Feed Finder and Feed Calculator help you choose and size the ration.

Feeding rules that protect the gut

Split concentrates into two or more meals, with no more than about 5 pounds of grain in a single meal for an average horse.
Make any change gradually over 7 to 14 days, including a new hay, since the gut bacteria need time to adapt.
Provide clean water at all times; a horse typically drinks 5 to 10 gallons a day, and more in heat or in work.
Give salt, either loose or as a block, and offer free-choice access.
Feed at the same times each day, and let horses rest after a hard workout before feeding grain.

Supplements: what helps and what does not

Many supplements have little evidence behind them, and some duplicate what is already in the feed. Ask first whether the horse has a real problem, then whether the diet already covers it. A hay-only diet can lack vitamin E, selenium or zinc depending on region, and a vet or a nutritionist can advise using a hay test. Hoof, joint and other targeted supplements may help specific horses, and the Supplement Needs Checker asks about your horse and points to the ones worth considering. Avoid giving several supplements at once, because overlaps can push selenium, vitamin A or other nutrients to unsafe levels.

Easy keepers and hard keepers

Some horses thrive on little, and others struggle to hold weight. Easy keepers need restricted pasture, lower-calorie hay and exercise. Hard keepers benefit from more frequent meals, higher-calorie forage, added fat and a vet check for teeth, parasites and ulcers. The Easy or Hard Keeper Finder helps decide which group a horse falls into, and the Body Condition Score Calculator tracks the result.

Common mistakes

Feeding grain to replace hay.
Measuring feed by volume rather than weight.
Switching feed suddenly.
Feeding moldy or dusty hay.
Adding supplements without checking what the diet already contains.

Feeding needs vary from horse to horse, so ask your veterinarian or an equine nutritionist for advice on horses with health problems such as laminitis, Cushing's disease or insulin resistance.

Frequently asked questions

How much hay should a horse eat per day?

At least 1.5 percent of body weight in forage, and many horses do best near 2 percent. For a 1,000 pound horse, that is 15 to 20 pounds a day, plus an allowance for hay that is wasted.

Does my horse need grain?

Not always. Many horses are well fed on good hay or pasture and a ration balancer. Grain or a fortified feed is for horses that need more calories, such as hard keepers, horses in hard work, seniors and broodmares.

How quickly can I change my horse's feed?

Over 7 to 14 days for concentrates and also for a new batch of hay if it is very different. Sudden changes can upset the gut and increase the risk of colic.

Tools used in this guide

More guides

Figures in this guide are general guidance for planning. Every horse is different, so work with your veterinarian, farrier or trainer on health, hoof and training decisions, and read our disclaimer.