Can Horses Go Without Food Overnight? (And What It Means for Ulcers)

Horses are built to eat little and often — so it’s completely normal to wonder whether they need to eat at night, whether a horse can safely “fast,” and whether short periods without feed increase the risk of ulcers or other health problems. The short version is this: horses can go without eating for short periods, but regular overnight fasting (especially for many hours) is not ideal, and for some horses it can contribute to issues like gastric ulcers, hindgut upset, and behavioural stress. Let’s unpack why.

How a horse’s digestive system is designed

A horse is a grazing herbivore with a digestive tract designed for a steady trickle of forage, not large meals with long gaps. There are a few key features that explain why feeding patterns matter so much:

1) The horse’s stomach is small

Compared with humans (and even compared with many other animals), the horse’s stomach is relatively small for its body size. This makes sense for an animal designed to graze constantly rather than eat two or three big meals a day. A horse can certainly consume a large feed bucket, but the stomach itself is not designed to be filled and then left empty for long stretches.

2) Horses produce stomach acid continuously

This is the big one. A horse’s stomach produces acid all the time, not just when food is present. In a natural grazing pattern, forage is frequently entering the stomach, helping buffer acidity and creating a fibrous “mat” that reduces acid splashing upward.

When a horse goes for long periods with no forage, there’s less material to buffer that acidity — and that’s one reason fasting can increase ulcer risk, especially in the upper (non-glandular) part of the stomach.

3) Saliva is made when they chew

Horses don’t produce saliva continuously — they produce it when they chew, especially when chewing forage. Saliva helps buffer stomach acid. Less chewing = less saliva = less buffering.

4) The hindgut relies on steady fibre fermentation

Most of a horse’s energy comes from fermenting fibre in the hindgut (caecum and large colon). The microbes that do this work best when they get a consistent supply of fibre. Large gaps without forage can disrupt fermentation patterns, contribute to gas, discomfort, and in some horses, increase the risk of colic.

What horses would do in the wild

If you watch horses living in a more natural environment, they are rarely “meal eaters.” Horses in the wild (or feral herds) typically spend many hours a day grazing — often around 14–18 hours depending on forage availability, weather, and herd dynamics. They do rest, doze, and move about, but they tend to return to grazing frequently.

At night, horses don’t usually stop eating entirely. They may graze less during certain periods, but it’s normal for them to graze on and off overnight, especially if conditions are comfortable and feed is available.

So if we ask, “Do horses need to eat at night?” the natural-history answer is: they’re designed to have access to forage across the whole 24-hour cycle, including overnight.

Can horses fast?

A horse can fast in the sense that it can go without eating for a short period and survive — for example:

• during travel

• around veterinary procedures

• while waiting for dental work

• if temporarily off feed due to illness

• if stabled for a short time without access to hay

But “can” and “should as a routine” are different. Routine fasting isn’t ideal, and the longer the gap, the more likely you’ll see negative effects in digestion, behaviour, and stomach comfort.

What counts as “too long” without forage?

There’s no single number that applies to every horse, but as a practical rule, many horse managers aim to avoid forage gaps longer than 4–6 hours, particularly for horses that are ulcer-prone, stressed, in work, or stabled for significant periods.

An overnight gap can easily reach 8–12 hours if a horse finishes its hay early — and that’s where problems can creep in.

Does fasting increase the risk of ulcers?

It can. Gastric ulcers are complex and influenced by many factors (stress, exercise intensity, diet, management, NSAID use, and individual susceptibility), but long periods without forage are a well-known risk factor, especially when combined with high-starch meals or significant time stabled.

Here’s why it matters overnight:

• If a horse runs out of hay early in the evening, its stomach can sit acidic for hours.

• Without chewing, saliva production drops.

• Without fibre, there’s less buffering and less protective “mat” in the stomach.

• Some horses also experience stress or frustration when they’re hungry, which can further worsen gastric health.

Not every horse will get ulcers from one night without hay. But repeated fasting — especially the kind that happens when hay is fed once and finished quickly — can increase risk over time.

Other impacts of overnight fasting

Ulcers are the headline concern, but they’re not the only one.

Behaviour and stress

Horses that are hungry can become:

• irritable or anxious

• more likely to weave, crib, or display stable vices

• pushy at feed time

• aggressive toward paddock mates around hay

For many horses, having something to nibble reduces stress and promotes calmer behaviour.

Hindgut health and colic risk

Long gaps without fibre may contribute to changes in hindgut fermentation. Horses that alternate between long “empty” periods and big meals can be more prone to digestive upset.

Weight management complications

Some owners try fasting to help weight loss. The problem is that restricting forage too aggressively can backfire — not only by increasing ulcer risk and stress, but by causing a horse to “yo-yo” between bingeing and fasting. Weight loss is usually better managed with low-sugar forage, slow feeders, appropriate turnout/movement, and a balanced ration rather than long feed gaps.

So… do horses need to eat at night?

Most horses do best when they have access to forage overnight, or at least when they don’t face long periods with an empty stomach. That doesn’t mean they need a full hay net constantly overflowing — but it does mean we should aim for a management setup where forage lasts through the night as often as possible.

Practical ways to reduce overnight fasting

Here are strategies that help match natural eating patterns:

1. Use slow feeders or small-hole hay nets
   These extend eating time without necessarily increasing calories.

2. Feed the majority of hay in the evening
   If your horse is stabled at night, a bigger portion in the last feed can help reduce gaps.

3. Split feeds if possible
   Even a late-night top-up (when practical) can help ulcer-prone horses.

4. Choose appropriate forage
   For easy keepers, look for lower sugar hay and manage portions via slow feeding rather than removing forage completely.

5. Avoid large, high-starch meals
   Large grain feeds with long gaps can worsen gastric acidity patterns. If concentrates are needed, keep meals small and feed alongside forage.

6. Consider a “fibre snack” before exercise or travel
   A small amount of hay or chaff beforehand can help create that protective fibrous mat in the stomach.

When fasting might be necessary (and how to do it safely)

Sometimes fasting is unavoidable — for certain veterinary procedures or sedation. In these cases, follow your vet’s instructions. If you’re unsure, ask specifically whether forage needs to be removed, and for how long. Often, short, controlled periods are manageable, especially if they’re not part of daily routine.

The bottom line

Horses are not designed to be “empty” for long stretches. Their digestive system is geared toward near-constant forage intake, with continuous stomach acid production and a hindgut that thrives on steady fibre. In the wild, horses graze on and off through the night — and our management should try to mimic that pattern.

Short fasting periods happen and aren’t automatically harmful, but regular overnight forage gaps can contribute to problems, including an increased risk of gastric ulcers, digestive upset, and behavioural stress. If you can, aim to keep forage available overnight — using slow feeders, smart portioning, and suitable hay choices — so your horse’s gut stays comfortable while they rest.