When I was a kid, they guys would manually toss the bales up to the guys on the wagon. They would in turn keep the momentum going and stack them. Take some strong guys to stack bales on the top when it must be about 12 feet tall. Not to mention summertime temperatures and humidity in the middle of Ohio.
Not that many years ago we lost a good part of a young family here in VA due to Methane in a manure pond. Sometimes education is a good thing.
My neighbors (now in their eighties) still have a picture of me and their daughter the night I took her to the Homecoming Dance (1969.) Haying had ended just a couple weeks before and I look like a 120 lb scarecrow in a blazer that hangs off me.
It usually took till the following June to get back up to 160 lbs.. Man, that was hard work.