Home » How Much Hay Should A Horse Eat: A Definitive Guide

How Much Hay Should A Horse Eat: A Definitive Guide

Horses love to eat…and eat…and eat.  As natural grazers, most of their day is spent nibbling grasses.  If your horse doesn’t have access to fresh grass, it is important to provide him with good quality, clean hay.  But how much hay should you feed your horse?  After consulting several veterinary texts and from tracking my own horses diet, I’ve found an easy recipe for calculating how much hay to feed.  

Horses should be fed by weight not volume.  They need enough roughage to equal at least 1.5 to 2 percent of their body weight each day.  For a 1,000 pound horse, that equates to 15 to 20 pounds of hay.  Health, age, size, grazing and activity levels all influence how much your horse needs to eat to remain healthy.

Let’s go over the basics of feeding hay to horses so you can make sure your equine is happy and getting enough to eat.

How to measure out hay for horses

A standard square hay bale breaks apart in “flakes” which can easily be weighed on a scale.  A hanging scale or even a bathroom scale makes for quick and accurate weighing.  Once you get “a feel” for how wide the flakes should be you can quickly dole out the appropriate amount.  Of course, you can weigh the hay each and every time if you so choose.

A 5 inch flake is not going to weigh the same across all types of hay.  Some hays, such as alfalfa, are denser and have a smaller flake to weight ratio.  Grass hay has smaller blades and packs a little fluffier requiring a larger flake size for the same weight.  

For large hay bales, including round ones, you won’t likely be pulling flakes off to measure and feed.  The flakes will be too big and messy.  These types of bales are used for bulk feedings or are left out for free access which we will discuss later.

How to estimate my horse’s weight

In order to decide how much hay to feed, you need to know how much your horse weighs.  The simplest way to estimate this is to measure his heart girth (circumference around their body behind front legs) and body length (from chest to butt) in inches. 

Use the following equation to estimate your horse’s weight in pounds:  

(heart girth x heart girth x body length) / 330 

For example, a horse with a heart girth of 73 inches and body length of 64 inches should weigh approximately 1,033 pounds.

(73 x 73 x 64) / 330 = 1,033

How many times a day should I feed my horse hay

Horses that have access to good quality pastures don’t need a lot of hay.  In fact, during the summer months, you may not have to give them any.  You can supplement with a little bit of hay each day if you want to provide some variety.

If the grass quality is poor or you only have dirt paddocks, providing hay each day is essential.  Many horse owners feed twice a day: once in the morning and once at night.   This means for a 1,000 pound horse, you need to feed at least 10 pounds of hay each time. 

For many horses this schedule works fine.  However, since grazing is a natural thing for horses, some may get bored when they don’t have something to munch on during the day.  Keep an eye on your horse for signs of boredom.  If this is the case and you can fit it into your schedule, split hay feedings into three times a day. 

No matter how many times you feed a day, make sure all portions add up to the daily total determined by your horse’s weight and health requirements.  If your horse works hard, is a pregnant or nursing mare, or recovering from illness, they will need more nutrients and calories.  This is usually in the form of supplements and grain but increasing their hay portions is also important.

If you don’t want to lock yourself into feeding your horse three times a day, or even two, see if your horse can handle having free access to larger quantities of hay.

Should horses have free access to hay

If you want to switch your horse from twice daily feedings to free access, there are a few things to keep in mind. 

  • Providing unlimited hay is just like turning your horse out to pasture.  They can eat when they want.  You are no longer controlling exact daily amounts.       
  • When you initially introduce the large bale, your horse will be excited and will probably eat for a long time.  They have to adjust from eating everything up during meal time to having access whenever they want.  This may take a couple days for them to calm down and learn that you aren’t going to take it away.
  • To prevent colic issues, feed grass hay varieties.  Alfalfa is a ‘hot’ feed and should always be fed in monitored quantities because it’s high in protein and provides too many calories.
  • If you use large bales and depending on how many horses you have, you can go a week or more without having to set out a new one.  
  • Bulk feeding is messier because your horse will dig around for the choicest pieces first verses eating an entire flake each time.  Hay bins are available that help contain the hay and keep it from exploding all over the yard.  Providing a cover to keep the hay dry will also help with prevent wastage.  

Can a horse eat too much hay

Horses, like all animals, can eat too much of one thing at one time.  This usually happens when they gain access to large amounts of feed that is new and tasty.  It’s pretty much a “kid in a candy shop” scenario.  

Eating the same thing over and over gets boring even for horses so when presented with something new, they are going to enjoy it.  However, logic and portion control is not something horses are good at.  They usually eat until their stomach hurts.  

Like I mentioned above, free access feeding can cause this but usually only during the initial excitement.  If you accidentally leave the feed room door open or set a bale of hay within reach, your horse will most likely help himself.  Eating after all, is his favorite past time.

Most horses will slow down or stop eating when they get full but sometimes a stomach ache has to trigger that.  This usually clears itself up with time.  There are always extreme cases so make sure to contact your veterinarian if you notice your horse isn’t feeling well for an extended amount of time after eating too much.  

How long will a bale of hay last

Based on the 1.5-2% rule, a 1,000 pound average horse needs to eat 15 – 20 pounds of hay a day.  This works out to about one bale per week if using a standard two-string bale.

A simple calculation of dividing bale weight by the number of pounds per day will give you how many days the bale should last.  However, unless you are going to weigh each and every bale you buy, using typical bale weights will give you a close estimate.  It’s always better to buy a little bit more than to run out.  

Bale SizeBale Weight# Days for 1000 lb Horse
Standard Two-String50 – 100 lbs2 – 6 days
Standard Three-String100 – 150 lbs5 – 10 days
Large 3’x3’x8’760 – 850 lbs38 – 56 days
Round Bale1000 – 120050 – 80 days

As you can see, the larger the bale, the longer it will last.  But before you run out and buy the biggest bales you can find, keep in mind that you need adequate dry space to store them.  You also need equipment capable of moving hundreds of pounds of hay.  

What hay is best for a horse

We’ve talked about how much hay in general a horse should eat.  Now we need to consider the type of hay because that also plays a roll in determining how much they should have.

There are three basic types of hay:  grass hay, legume hay and grain hay.  With several varieties within each group.  There are also first, second and third cutting ratings for hay.

This topic is too large to include in this article so make sure to check out my other article which covers it in great detail: The Best Hay For Horses.

Final thoughts

Hay makes up the bulk of your horses’ diet when they are not actively grazing on grassy pastures.  It’s important to give them the correct volume that meets their current nutritional needs.  Under feeding and over feeding your horse can lead to health issues, especially if it’s continued over a long period of time. 

Start with the basic 1.5-2% rule and add more hay depending on the situation.  An inexpensive scale is the easiest way to confirm that you are flaking off enough hay from the bale.  After awhile, you will be good at feeling the appropriate weight.