A sometimes overlooked item in barn building is door hardware.
Not just what the door is assembled with, which is a concern for horse health and should be factored in. But also how the door is moved.
Sliding doors in barns are optimal for a variety of reasons, space being one of the more important. Stall doors can be large and heavy and that means have secure rails and guides. But remember that your horse is going to be stepping through that space frequently. Innovative Equine Systems has come up with a great solution that you can see in this video.