You will need space for equipment and feed storage in your barn. However, the most important part of your stable will be the stalls for your horses. Box stalls for a horse should be an average of twelve feet by twelve feet. A larger horse will be more comfortable in a larger stall, and a small pony will be happy in a somewhat smaller stall.
Stalls for broodmares who will foal are often larger than a regular stall. The easiest way to accommodate a mare and foal is to make the partitions between two stalls removable, so that the mom and babe can have a double stall. The two stalls can be returned to their original sizes and use once the foal has been weaned. A larger stall can also be useful for horses on stall rest.
Standing stalls should be about five feet wide and eight feet deep. Again this depends on the size of the horse, but there should be enough room to stand and lie down easily. The tie rope should be positioned high enough that the horse cannot put a foreleg over it.
Stall walls between the horses can go to the ceiling or may be a bit lower so horses can see each other easily. Horses are happier if they feel they are with companions. Six feet high or higher ensures that horses can't get over, or caught up on the wall. Some people fill in the open space with metal bars or heavy square wire screen so horses can see, but not touch each other. Be sure that the spaces in the wire, or between the bars is small enough the horse can't get caught.
A few other considerations:
- The ceilings should by high enough to allow the horses to move their heads up and down fully. Nine feet or higher is best.
- There should be good natural light and ventilation without being drafty in cold weather.
- Stables should be planned so they do not flood in heavy rain or snow-melt.
- Floors should dry quickly, provide good traction and be easy to clean.