There's a job I never was very good at, was too weak to throw bales that high for and length of time, that's a lot of work lol.
Started out as a kid, helping my uncles with the small squares. Regular farm hay wagon, so the deck was pretty high to begin with. Stacked up quite a few layers full width of the deck, then tapered in at the very top to a single ridge. With a full wagon, I'd be riding on the tractor with one uncle, heading back to the barn.
I can still see my other uncle, sweeping the field as needed. An occasional green (undried hay) bale was left to the end, to be segregated on the very top of the load, so it would be tossed aside before unloading at the barn. If you've ever picked up a green small square by hand, they aren't light..... my uncle would just grab a pitchfork, stick it into the bale, and fire it all the way onto the top of the tiered load w/o even trying hard.
That uncle was no more than 5' 5", 110#, but he was just bone and muscle. Olde school farm tough is a different league altogether.
Rgds, D.