Horse Stress

Horses, like people, suffer when stressed and can become ill as a result of stress. Consequently, one should try to avoid (or minimize) the amount of stress our horses experience.

There are three main types of stress:

  • Constant Stress. This is stress which a horse is under repeatedly, often as a part of its daily routine (e.g. a horse which is bullied each day by other horses on its pasture).  Such stress can affect the horses behavior, for example making it nervous and more difficult to handle. It can also affect the horse' health, resulting in the development of ulcers and general reduction in the efficiency of its immune system.
  • Occasional Stress. This is stress which occurs from time to time, but not daily. For example, the stress of transporting a horse to the occasional competition. Such stress, unless it is extreme (see traumatic stress below) normally has relatively little effect on the horse once the event is past. The main exception is if the stress conditions are repetitive. For example, a horse which has an unpleasant experience every time it is taken to a competition may eventually develop an aversion to competitions.
  • Traumatic Stress. This is a high-stress event, such as a very painful injury. Such events can result in mental and behavioral issues. For example, a horse which is injured during transport may develop an extreme fear of horse trailers and refuse to enter them. Traumatic stress can also be caused by extreme fear, so a horse which is very frightened, even if it suffers no injury, may develop the same mental and behavioral issues. For example, a horse which is locked in a horse trailer during fireworks may be extremely frightened by the noise and develop a phobia of trailers, refusing to enter them in future.

As the above shows, stress can have the same detrimental effects on horses that it has on people. That is, it affects their physical and mental well-being, as well as possibly resulting in the development of phobias or other problems. Unfortunately, many horse owners are unaware of the ways in which they (or the establishments where the horses are stabled) cause unintentional stress. Consequently, the various sources of stress and how to avoid them are discussed below.

Isolation Stress

Horses are herd animals and very much social creatures. In the wild, they not only interact with other horses but in fact are largely dependent on a herd for survival (for example, other horses keeping watch for predators). Consequently, a horse on its own will be lonely and unhappy. A horse must have at least one companion to be happy and preferably several. No matter how much you love your horse and even if you spend a fair bit of time with it, you cannot fill this roll (especially since, from a horse's perspective, a person looks and behaves like a predator rather than a fellow horse). The companions do not have to be other horses, their are many cases of horses bonding with other types of herbivores (e.g. goats), although it is more likely that other horses will make acceptable companions.

If you own only one horse and keep it on your property, it is essential to the horse's happiness that you find a companion for it. In many cases one can find an older retired horse which is available for free (from its owner or from a rescue organization), as many owners do not want a horse once its working life is over. Such cases allow you to obtain a companion horse at no cost and at the same time do a good deed of providing a home for an unwanted but deserving horse.

Social Stress

Just as not all people get along, so not all horses get along. In fact, the relationships of horses are more similar to the relationships of school children than to adults in two important respects. The first is that like school children (as opposed to adults), horses are put into groups not of their own choosing. The other is that horses, like young children, lack the social constraints and considerations that one hopes for in adults. As a result, among horses it is not uncommon to find the same bullying and social isolation that one can see in a children's playground. In some cases this can be extreme, where a horse is constantly bullied, including being chased and attacked, by one or more of the other horses in the herd. Of course this can have a detrimental effect on the horse's well being.

A number of larger stables report that such issues are reduced if one does not mix sexes. In other words, mares and gelding should be in separate herds and in separate pastures.

It also helps to have horses of a similar age, size and physical health. Some horses are natural bullies and will look for a smaller, older or sick horse to pick on. Avoid providing them with potential victims. On the other hand, some horses are naturally gentle and can be easily matched with an old or sick horse. Knowing and understanding the character of the individual horses allows one to judge which horses will get along and form compatible groupings.

Unfortunately, it is not always possible to predict with certainty how horses will react when grouped together. Consequently, when making any changes to a herd (adding new horses or removing existing horses), one should carefully observe the herd during the following days and weeks to make sure that the resulting changes to the social interactions are acceptable.

In the stables, one should carefully arrange the horses so that compatible horses are box neighbors. Placing horses that strongly dislike each other in adjacent boxes needs to be avoided.


Like people, a bored horse is an unhappy horse. Furthermore, the main source of behavioral problems in horses is boredom.

A horse has three main sources of mental occupation and interest (see mental stimulation for details), which if provided in adequate quantities will avoid these issues:

  • Social. As discussed above, a horse needs to spend time in a herd (small or large) with reasonably compatible relationships.
  • Pasture. Horses are naturally used to open spaces, where they can experience many different types of physical stimulation (walking, running, grazing, feel of wind, various smells, looking about, etc.)
  • Food. Horses need to spend a fair bit of time eating, for both physical and mental health. See feed and behavior for discussion.

Change and Uncertainty

Most animals, including horses, like stability. There is a big difference between change and variety. A large herd or a big pasture provides variety. However, being moved from one place to another or changes to the herd membership is stressful. One should try to keep change to a minimum.

Uncertainty is a related form of stress. A horse which is always handled by the same people and in the same way knows what is expected of it and how to behave. Variations in handling means that a horse does not know what is happening or what it should do, which not only is stressful for the horse but also means that the horse does not behave as well or as predictably as it could simply because it is confused. For example, a horse with many different riders, who have different riding styles (e.g. western versus english, hard reining versus soft reins) is confusing for a horse and results in a horse whose riding behavior detoriates to the lowest common base. Consequently, not only for the horse, but also for your own pleasure and ease, consistency is important.

One should strive for consistency with your horse in all things, even in small things. For example, if one leads the horse on the right hand side, one should always lead the horse on the right hand side.


A special case of 'Change and Uncertainty' is training. By definition, training is teaching a horse to do something it doesn't know (thus uncertainty) or doesn't want to do. As such, even the most gentle training will involve some amount of stress. As most trainers use force, as well as a certain amount of pain (e.g. spurs) in training, this of course increases the stress level. To a certain level, one can consider this acceptable (after all, school can be stressful for children, but we would not decide to not educate them on this basis). However, consideration should be given to finding a trainer who uses gentle and less stressful training methods. Also, adding some positive aspects (e.g. food, grooming, pasture time) during or immediately after training  will help the horse see the training in a more positive way.

Noises and Surprises

In the natural state, noises and surprises tend to be threatening activities (e.g. attack by a predator or other horse), so horses are easily frightened when exposed to sudden unexpected noises or surprises.

Aside from the stress aspect, this can be dangerous for the horse, nearby horses and nearby people. When a horse is frightened in this way, its natural reaction is to jump and then run away. They will often do this without first looking, which means that they can jump into nearby objects (injuring themselves), nearby horses (causing them to jump and panic) or nearby people (possibly injuring them). So, there are many reasons to avoid noises and surprises near horses, especially when they are in a building (e.g. stables).

To avoid this, one should never come up on a horse suddenly (e.g. coming around a corner) without the horse knowing that you are coming. Instead, one should start talking some distance away so that the horse knows that you are coming, rather than first hearing or seeing you when you are close.

Likewise, if one is going to be making loud or unusual noises (e.g. building or repairing stables), it is wise to first move the horses some distance away, preferably on open pasture, when they will not only feel safer but are also less likely to cause injury to themselves or others. If this is not possible, one should take reasonable safety precautions (e.g. don't allow anyone to stand in any open doorway, when they are likely to be run over by a horse) and introduce the noise gradually, carefully watching the horse to make sure that it is not frightened or panicked.

Confinement and Dark

In nature, a horse's best defense is to run away. For this they need large, open spaces and light (e.g. not pitch black). Consequently, these are the conditions under which a horse naturally feels most secure. Places such as a small, dark trailer are therefore naturally threatening and uncomfortable for a horse. Although one cannot completely avoid this, the closer one can come to the natural surroundings, the better. For example, a large box with good access to natural sunlight and with an opening to allow the horse to look outside will be much less stressful than a box which is small and dark, with the only views being internal.


Pain can be caused by an injury, illness (e.g. hoof abscess) or activities beyond the horse's physical capabilities. In many cases, a horses resistance to an activity is misinterpreted as a behavioral or educational issue, when it is in fact simply that the horse is in pain or that the requested activity causes it pain (see Hoof Shyness as an example). If a horse appears stressed, unhappy, depressed or mis-behaving then one should consider that pain or discomfort may be the cause.


The best treatment for stress is simply to remove the cause of stress. One should also provide a horse with an environment with lots of mental stimulation (see Boredom above), in an environment which it feels safe and is treated in a consistent way.

In some cases, stress may result in or contribute to the development of behavioral issues. In this case the required treatment depends on the type of behavioral issue and the individual horse. For further discussion, see behavior problems.