Hope nobody minds if I make a second post. (We're not being over-run this week it appears).
I just ran across this picture of my dad, loading hay bales onto a hay wagon in 1989. We always did square bales, even after most farmers moved to round bales. Round bales were bigger, and usually handled by a single person on a tractor, but we liked square bales. They were kept in a barn, so there was less wastage from the weather, and they were more appropriately sized for our sheep (most of our neighbors had cattle). But it was definitely more work to bale them and stack on the wagon, unload and finally stack in the barn. This was best done by at least 2 people. As you can see in this picture, Dad wasn't happy until the wagon was loaded with as many bales as it could hold.
I always regretted that the picture was cut off just above the wheels. They were neat metal spoke wheels, as this was an old wagon, maybe from the 50's.
This year we had more bales than usual, and stored some of them outside in a stack. Like the old-style hay stacks, some loose straw was scattered on top with the stems pointing outward to shed the water. (Straw works better than hay for this purpose, and cheaper too, so losing some straw to protect the hay is fine).
Each bale probably weighed 40 - 50 pounds.