Horses need extra cushion and dryness in their stalls to help promote healthy hooves and overall general health.here you have a few choices:
Straw, it´s the common bedding used by many, is not as absorbent as other available bedding, but is often relatively inexpensive and decomposes quickly in your compost, it also provides a nice soft bed for your horse.
Sawdust and Wood Shavings. Sawdust is high absorbing, but if your horse is prone to respiratory problems it should not be used. A better alternative is wood shavings. Wood shavings are easy to muck out and can be found easily. Processed wood shavings are more expensive, but are clean and dust free and do not contain any toxics that may be harmful to your horse, but sawdust and wood shavings do not decompose well in your compost pile.
Rubber Matting. Many advantages such as being completely dust free, drains well and is warm, you can add a little bedding, like straw, to make a bed more comfortable for you horse to lie in or if the drainage under the matting is not adequate.