One of the farm boys talked about haying season. He recounted a story of how one time he was pulling a wagon with a load of hay bales. The bales were the circular, roll-type bales and not the cube kind.
One time one of the huge roll type bales fell off the wagon, rolled down a hill, and almost smacked into a car driving on a road below the hill. I then assumed that particular action must occur many times during haying season across the country. The area where I live is very hilly and many farms have their fields on hillsides. Something to think about as you're driving through the hilly countryside during haying season.
I often will see a large round bale that has fallen off a truck in the ditch. Not worth stopping to pick it up as it it too dangerous.