Recommended Code of Practice for The Care and Handling of Farm Animals.
The most commonly used flooring in stables is concrete. If the surface is roughened it is non-slip. Concrete, pavers, or stone floors will not drain naturally, and drains may have to be placed in stalls. Many stables do not have drainage however, so stalls must be well cleaned to avoid ammonia build up. Hard flooring such as pavers or concrete are also easier to disinfect and can be hosed down if necessary. These floors are harder on a horse’s legs though. Many people put stall mats made of rubber like material under the bedding for greater comfort.
If you have sandy soil you may decide to leave the earth and not lay down a solid floor. This flooring is easier on the horses legs, may be warmer and quieter than an un-matted solid floor. Earth floors are harder to clean, and will need digging out and replacing if dirt becomes too saturated.
Dust, smells and bacteria from droppings can stagnate and cause significant health problem. Having a proper ventilation is a crucial factor to ensuring healthy animal. Windows and gable vents provide natural ventilation and lighting. You can incorporate as many as possible in your stable design. They should be covered with a grill or mesh so horse can’t break the glass or perspex. Windows that swing open may work better over the long run then sliders that tend to fill with dirt and chaff making them stick.