This might be a stupid question, if so, I am sorry. I board my horse at a facility where ethe barn is made of concrete. Ceiling is wood. Hay is stored upstairs and dropped through holes in the ceiling at feeding time.
Obviously, no one is allowed to smoke at the barn and no one does. Is this more safe in terms of fire risk because the barn is concrete, or if a fire started upstairs in the hay loft would it be just as bad as a wooden barn?
Any time you have hay in a loft above the horses, the air quality is not as good in that stable.
There are hay and mold particles floating around in many times larger numbers in those barns than in those where hay is not kept in there, or only in a corner on the ground floor.
The chances of a fire I would say are there wherever you store hay and of course, on a loft, on wood over stalls, that is a no brainer, the risk is larger than if the hay was not kept there.