My Grandfather had a 49 Diamond T pickup that we used to stack up to 50 bales on. The pile was twice as wide as the truck and the only reason we quit piling on the bales was because we couldn't throw them any higher.
When I was twelve, I almost got the crap beat out of me when I hit a ground hog hole with an almost full load of hay. The farm hand was on top stacking the bales and almost fell off with all that hay.
Doc