When I first asked, “does a horse need light at night” it seemed a stupid question, but to humor my friend, I did some investigation, and there is much more to the question than I first thought. In fact, after answering my friend, I found it so fascinating that I thought I would share the answer here as well.
The thing that shocked me most is that even among so-called equine professionals, there is disagreement. Some say they always have a night light in their stables, while others say that there is no need. If the experts do not know, how are we mere mortals expected to do the right thing?
Reasons Why Horses Should Have Light at Night
1. Brings Forward Breeding Season
Light, naturally coming from the sun, affects all living things and produces a “Circadian Rhythm.” This 24-hour rhythm controls nearly all physical and biological processes. It is well known that leaving mares in a lit stall will advance the breeding season, and the result is that foals are born earlier in the year. Exposing a mare to 100-watt lighting starting December 1st can bring forward the breeding season by up to thirteen weeks.
2. Security
Some people feel they need security lights on in a barn. Increasingly people are turning to LED lights as the lights are cooler and thus less chance of causing fire, and also, the light spectrum from LED is better for a horse than regular lighting.
Reasons Why Horses Should Not Have Light at Night
1. Because Horses are Prey Animals, They Get Cautious at Night
Horses are prey animals and therefore programmed to be on the lookout for predators. At night they become much more cautious and stressed. Some horses that will load into a trailer happily in the daytime will refuse at night. Put a light in the trailer, and problem-solving. It is the same when they enter the stalls. The reason is that although horses can see better in the dark than humans, they have trouble with light and shadows, so the light resolves that problem. Once they are in their stalls, as long as they have minimal light, their eyes adjust, and they can see well enough to relax. This may be a window that lets in moonlight, so you can turn the lights off as they will acclimate to the dim light but not get spooked by shadows.
Suppose you have any doubts about the “Prey Animal” theory. The need to be ready to detect and flee from a predator is why horses mostly sleep standing up. They can quickly run if a predator appears. They do not have time to stand up.
Putting aside the fact that horses sleep most of the time standing up, horses’ sleep patterns are very different from ours. The horse will be awake, grazing, and moving around most of the night, with limited two-hour spells of sleep. During the night, they will grab 2 hours of sleep standing up, and another period where they may lay down for Rem sleep, which is the most restful.
This is also why horses are more relaxed in a group. First of all, there is safety in numbers and more chance that one of several horses will spot danger than a solitary one. Secondly, when there are two or more horses, they will generally sleep in turns, with one or more staying awake.
2. Lights Attract Bugs
You should not have lights burning bright in your stable at night because the lights will attract bugs, and these bugs will disturb the horses. This is why some people turn their horses outside at night and stable them in the daytime.
3. Horses Have Better Night Vision Than Humans
Horses have big eyes with some features that are normally only found in nocturnal animals. This is so they can see predators approaching. They can see quite well in dim light and are quite comfortable doing so; after all, wild horses live quite happily without night lights. Horses cannot do adjust between bright light and dark quickly. It takes them time to acclimate, and so turning a light on or off frequently will disturb them at the very least.
Conclusion
Low light may not be something that we humans find comfortable, but your horse that had ancestors who wandered around outside at night, seeing by starlight, are quite comfortable with low light. It is the most natural way. So when talking about stables, a large open window that allows starlight may be all the horse needs. If you will supplement the lighting so that humans can also see, then lows powered warm color LED lights to offer the best nighttime environment. In the daytime, a more powerful bluer LED light will replicate natural sunlight better.
