Horse lying down: is it normal rest or a medical emergency?

Do horses lie down? (Understanding normal sleep patterns)

Yes, healthy horses lie down every day, and they have to: a horse needs to lie down to get proper REM sleep and complete a full sleep cycle. Kelemen and colleagues write that an inability to lie down results in REM sleep deficiency, which can seriously affect welfare and health. As prey animals, the same study notes, horses lie down only when they feel comfortable doing so.

The Vienna team's review of earlier research puts adult horses down for 3 to 15% of the day, which by our own arithmetic is roughly 43 minutes to 3.6 hours, and sensors on 83 sanctuary horses measured anything from 0 to 319 minutes a day. The minimum is clearer: Kelemen and colleagues and a Swiss study by Burla and colleagues both say horses need at least about 30 minutes of lying down a day, of which only 3.5 to 4.5 minutes is REM itself. Some popular sites turn that into "30 minutes of REM sleep", which is a larger claim than the studies make.

Plenty of owners rarely see it happen. Dr. Katherine Houpt of Cornell University told Chewy that most horses sleep deepest at night, when humans aren't at the barn, and Chewy suggests checking for bits of bedding stuck to the haunches in the morning.

Sternal vs. lateral recumbency: how horses lie down

Horses lie down in two ways: sternal recumbency, on the chest with the legs folded underneath, and lateral recumbency, flat out on one side with the legs stretched out, which is the position for REM sleep. Mad Barn gives those two definitions and, citing a veterinary behavior textbook (Beaver, 2019), says healthy adult horses spend 80% of their lying time on the chest. The 2022 review of equine sleep by Greening and McBride links REM sleep predominantly with lateral recumbency, and also with lying on the chest with the head propped on the ground.

REM sleep: why horses must lie down to sleep

Do horses lie down to sleep? For REM sleep, yes: horses doze and sleep lightly standing up, but they must lie down for REM, because in REM all the muscles relax. So do horses sleep standing up or lying down? Both. Standing sleep works thanks to the stay apparatus, which PetMD describes as a group of tendons and ligaments that keeps a horse upright with little muscular effort. Standing sleep can't replace lying down, though: Kelemen and colleagues write that less sleep lying down cannot be compensated for by more sleep standing up. So do horses sleep lying down every day? Healthy horses do, because that is how they get proper REM sleep.

Can horses sleep lying down for long stretches, and how much sleep do they need in total? Kelemen and colleagues give a total sleep time of typically 2.9 to 3.5 hours a day, with REM only 10 to 15% of it; our guide to whether horses sleep standing up covers how long horses sleep, in what pieces, and how the stay apparatus works.

Signs of a horse lying down comfortably

A horse lying down comfortably looks sleepy and relaxed: ears no longer upright and eyelids partly or fully closed, which Greening and McBride list as behavioral markers of sleep, breathing no faster than his usual resting rate, and afterward he gets up easily, shakes and goes back to eating.

Body language indicators

• Ears and eyes. Greening and McBride list ears that are no longer upright and eyelids that are partly or completely shut among the behavioral markers of sleep in horses, along with the muzzle on the floor when he lies on his chest.
• Twitching in REM sleep. PetMD says that during REM a horse's eyes move rapidly and he may twitch the ears or skin, blink, flare his nostrils or paddle his legs. Paddling legs in REM sleep is normal; repeated rolling belongs on the colic lists below.
• Breathing. An increased respiration rate is on Penn State Extension's list of colic signs, so a resting horse should be breathing at his own normal rate. Our guide to normal horse temperature, heart rate and breathing shows how to count it.

Environmental cues

Horses lie down when and where they feel safe, and according to Chewy's article that depends on lighting, bedding, herd dynamics and past experiences.

• Bedding. Houpt says freshly bedded stalls often prompt a quick lie down, which anyone who has watched a horse drop into a fresh bed before the wheelbarrow is out of the stall will believe, and that horses tend to sleep longer on straw than on shavings. In the Swiss study of 38 group-housed horses, horses with no bedded area rarely lay down, and lying time rose as the bedded area grew.
• The herd. Greening and McBride describe horses in a herd taking turns lying down and standing up as a supposed rota system of group vigilance, and note that stabling a horse in isolation removes that shared safety.
• A change of routine. One study summarized in the same review found that horses lay down more at night for six weeks after moving from overnight turnout to overnight stabling.

The danger zone: when a lying horse means distress (colic and pain)

A horse lying down signals distress when it comes with restlessness or pain: getting up and down repeatedly, rolling, pawing, looking at the flank, sweating or not eating, or lying down much more than usual and going straight back down after you get him up. Dr. Doug Thal of Horse Side Vet Guide names colic the most common reason for a horse to suddenly lie down more than normal or to get up and down repeatedly.

Red flags: signs of colic and injury

Merck lists lying down, rolling from side to side, pawing, looking back at the flank, sweating, loss of appetite and fewer droppings among the most common signs of colic, and notes that a horse with colic rarely shows all of them. Penn State lists lying down and rolling often, and UConn Extension lists getting up and down frequently.

Dr. Houpt's rule of thumb, as she told Chewy: a horse who is down for more than 30 minutes and then rises and doesn't shake deserves a closer look. Quiet lying can be colic too, and many owners wouldn't call about it. In a UK survey by Bowden and colleagues, fewer than half of horse owners said they would call the vet for a horse lying down quietly; most would rather keep watching.

Painful feet keep a horse down as well. Merck says horses with chronic laminitis are usually extremely lame and may spend a lot of time lying down. The American Association of Equine Practitioners (AAEP) doesn't list lying down as a laminitis sign, so check for the ones it does name: lameness, especially when turning in circles, heat in the feet, an increased digital pulse, a hesitant gait as if walking on eggshells and a "sawhorse stance" with the front feet stretched forward. The AAEP says to treat suspected laminitis as a medical emergency. Chewy's article adds hoof abscesses and advanced thrush to the foot pain that can keep a horse down.

Then there is the horse who can't get up. PetMD's Jennifer Rice DVM calls a down horse a common equine emergency and lists causes from injury and muscle disease to neurological disease such as equine protozoal myeloencephalitis (EPM). Healthy horses can also get cast, stuck in a position where they can't get up, such as close to a stall wall, and Rice notes this happens more often to older arthritic horses. Before you call, Rice suggests a feed test if you are unsure whether he is down from illness or colic: many sick horses aren't interested in hay or grain, while a horse that is stuck because of lameness or a mechanical problem often still eats. Thal likewise suggests offering a handful of feed he would normally eat eagerly and noting the response. No veterinary source gives a safe time limit: Rice writes that "there is no definitive time that is safe", and a 2009 University of Illinois report says the sooner a down horse is up, the better.

While you wait, the sources agree on a few things:

1. Let a quiet horse lie. The BHS says that allowing your horse to lie down or roll does not make colic worse or cause a twisted gut. Penn State and Thal both say to let a horse that is lying quietly stay lying down.
2. Walk only if it helps. If he keeps getting up, lying down and rolling, Penn State says walking may ease the pain, but not if he is lame or sore. Thal says your vet might advise walking, and the BHS says not to force a horse that resists.
3. Give nothing, and take the feed away. Penn State says to avoid giving any medication unless your vet tells you to, because it can mask the signs. With suspected colic, Penn State says to remove all feed from the area but a water bucket can stay; the BHS says to remove feed, hay nets and water buckets from the stable.
4. Stay safe. Penn State warns not to get in the way of a rolling, thrashing horse. Rice advises approaching a down horse from the back or the head, away from the legs, and having a second person with you, one of you with a phone.

A short video of how he lies down and gets up, as Chewy suggests, shows your vet more than a description over the phone.

Sleep deprivation in horses

A horse that doesn't feel safe or comfortable enough to lie down can become REM sleep deprived, and the giveaway signs are sudden collapses and scrapes on the front of the knees and fetlocks. In the Vienna study, eight horses showed those signs. All of them had chronic orthopedic disease, and they lay down for an average of about 8 minutes a day, compared with about 74 minutes for the other horses. PetMD lists inadequate bedding or no comfortable place to lie, a change of environment or routine, long trailer trips, and orthopedic or neurologic problems among the causes. If your horse never seems to lie down, look for scraped knees and ask your vet about pain; our guide to sleep deprivation and how horses sleep goes into the details.

How to track your horse's resting habits (before an emergency happens)

You can only tell that your horse is lying down more than usual if you know his usual: Dr. Thal of Horse Side Vet Guide writes that every horse is an individual, so note on ordinary days how often, how long and how he lies down. Some rest lying down more than others, he adds. The BHS says that if you've recorded what's normal for your animal in advance, it could help your vet once they've assessed your horse.

Thal's questions for your vet, plus a few of our own, make a good list of what to note, on a normal day and on the day something looks off:

1. When did you first notice it, and when does he usually lie down?
2. How long was he down, and was he flat on his side or on his chest?
3. What happens when you get him up: does he shake, and does he lie straight back down?
4. Does he have trouble getting up, or is he staggering or unsteady?
5. How are his attitude and appetite?
6. Will he walk freely in hand, or does he resist?

Write the answers down with the date and time, and who saw what. A horse you've just bought or moved is the hardest case, because nobody knows his usual yet; our guide to records for a new horse covers what to start noting in the first weeks.

Most of the time you aren't the one who sees it. The barn staff, a sharer or whoever does the evening feed sees him down, and whether that reaches you depends on whether they think it's worth mentioning. Our guide to sharing care covers how to agree on what gets passed on.

Conclusion and next steps

Most of the time, a horse lying down is a horse asleep; the time to act is when lying down comes with restlessness, pain or a horse who won't get up, or when it is clearly more than his usual. When you call, your vet will want to know when it started, what he did when he got up and whether he ate. Our guides to colic in horses and contacting your vet cover what to have ready.