Excessive confinement can be detrimental to equine healthSometimes a horse just has to be kept in a stall, but this is a very unnatural situation and can lead to a number of problems, both mental and physical. It has long been said that confinement is hard on a horses disposition. Indeed, most stable vices such as weaving, stall kicking, pawing, wood chewing, and cribbing (see accompanying story)are the result of a horse being cooped up for too long with nothing to do.
Horses confined in stalls are more apt to develop colic, stocked up (swollen) legs, or navicular disease than horses out at pasture. In nature, the horse was intended for wide open spaces, where he could wander endlessly and graze. Under natural conditions, he will spend up to 70% of his time grazing. He sleeps in short snatches for only about three hours out of 24. His almost constant motion aids his digestion and waste elimination (the horse at pasture rarely develops impaction or constipation) as well as respiration and circulation. His feet and legs are designed for moving; if he is stationary for too long, his circulation suffers.

Killer colic
The equine digestive tract works best when small amounts of roughage are continuously passing through. Colic is rare in free-roaming horses, but becomes the number one killer of domestic horses due largely to confinement and the unnatural feeds we give them. A high carbohydrate diet changes the bacteria population in the gut and increases the risks for colic and founder.
The mental stress of being confined, along with unnatural feeds and feeding times, can set up a horse for colic. It is a well-known fact that athletic horses (accustomed to plenty of exercise) who must suddenly be confined because of injury often develop digestive problems and colic. In such cases, the colic risk can be more deadly than the actual injury. An injured horse is usually confined for convenience of doctoring or ease of handling. Except for very serious injuries in which a horse should not move, most injured horses would be better off turned out in a small pen than in a stall, so they can move around a bit and function more normally.

Crippling confinement
Confinement is hard on feet and legs. Lack of circulation can cause lower legs to stock up. Stall confinement can also lead to navicular disease, the man-made crippler. It is a common problem in domestic horses, but very rare in the free-roaming equine. Many horsemen tend to overfeed and confine their animals, which is hard on circulation.
Usually the first step in breakdown leading to navicular disease is circulation troubleclotting of the tiny capillaries in the navicular bone. Reduction of blood flow eventually weakens the bone, and as it begins to deteriorate and die, the horse suffers pain and lameness.
Standing around in a stall stagnates the circulation in the feet and puts constant pressure on the joint cartilages that are normally dependent on motion for their circulation. Confinement and lack of exercise, especially in the young horse, if he has to stand on hard surfaces, can lead to navicular disease. Preparing youngsters for halter classes by keeping them in stalls and overfeeding them is a potentially dangerous practice.
A horse may also develop navicular disease if kept for long in a stall with a sloping floor, which will put his feet off-level. The forces on his navicular bone as he stands on an upslope are the same as if he had long toes and low heels, putting tension on the deep flexor tendon and thus more pressure on the navicular bone over which the tendon glides. Conversely, if the horse stands for hours on a floor that has a downward slope to the center of the stall, his feet will be in a toes-down, heels-up position (also hard on the navicular bone), even if his feet are shod in perfect balance.
The battle against navicular disease can begin in the stables. If a horse must be confined, a roomy box stall with a slight hump in the floor rather than a depression in the center is best.
A preferable battle plan, whenever possible, is simply to decrease the amount of time an animal is confined. Allowing a horse to spend time in an environment more closely resembling what nature intendedin open air, with grass to graze and room to roamwill have lasting beneficial effects, both physical and psychological.