[zzvyb6]

If the horses are kept mostly in the stalls, then a blue clay floor has antiseptic benefits to prevent thrush in their feet/hoof. (No Hoof, No Horse)
Use sawdust in the far corner away from a hay feeder to make it easy to scoop poop and absorb urine. They will eventually try to dig to China so watch for that. Always let the horses see each other so that they won't feel like escaping or pacing.

Keep the hay away from the stalls because horses give off a lot of moisture. That will cause the first layer of overhead hay to mold.

Keeping the horse out of the barn keeps the Vet out of the barn....