We will tedder the hay that is laying out in the field. That will fluff it up and let air and sunshine into it. It should finish drying out quickly then.
They catch fire if they are rolled to quickly, spontaneous combustion. Rolled hay goes through a heat, curing process. It is best to wait until they are cool to the touch before you stack them in the barn. These are not being stacked, just put into the barn until the rain passes.
I know about spontaneous combustion! I fear hay! I can't wait to have a separate building or at least fire-escapable barn.
Does this apply for cotten bales too? Last season we saw some on fire. Smoke seen a couple of miles before we got to it.