A blogger unfamiliar with horses wrote recently on a general community website asking whether he should be worried about a horse in his neighborhood that was lying down.
Wive tales aside, horses do sleep lying down. In fact, sometimes they'll even snore (because of increased pressure on their respiratory systems). Horses only achieve full REM sleep when they are lying down and they need 30 to 60 minutes a day of REM.
Because horses are prey animals, it's most likely that one or several horses will remain standing up (dozing) while others will lie down and sleep. These horses are guarding the herd, and they may take turns. Overall, research has shown that horses sleep or dose about three hours during a 24-hour period, with periods of resting in between.
Studies show that horses that do not get this 30 to 60 minute REM sleep over several days can become sleep deprived, just like humans. The symptoms are similar as well-a sleep deprived horse might suddenly close his eyes and buckle at the knees-falling asleep on his feet. When he is without herd mates, he may not rest well: Because of their herd nature, they need company that will alert them to a potential predator. Horses that live alone may be overly alert and may not sleep as well as those that have companions.
To solve sleep deprivation, make sure you find a companion for the solo horse; a goat, another horse or a donkey can help your horse rest better at night.
Build a safe shelter for horses that live outside-a place to get out of the wind, which can keep horses awake at night.
Identify whether your horse has any pain issues that may make it hard for him to lie down.
Like humans, horses need a safe, quiet and peaceful environment for sleeping. The best thing you can do for your sleep deprived horse is create it for him.