We had four hay wagons and two or three trucks for putting up hay - the wagons could handle about 120 bales each and the trucks about 160 each.
We never hooked a wagon to the baler. Tractor drivers could be as young as 5 years old and as old as 12 - more than 12 and you were picking up or stacking. A crew of 6 or 7 usually loaded and unloaded everything at least twice and that was with 10 to 30 miles from the farm to the field. We usually started the day walking milo fields cutting tall heads so you'd be soaked from foot to chest before you started handling hay.