At one time folks built temporary structures from little square hay bales, in between upright 2X4's, with a roof, the bales all standing on edge, kept even the outer bales reasonably dry from rain & snow. The saws were used to cut a bale to fit & then retied with the twine...I believe "Mother Earth " even ran an article or two on how to build structures from hay bales way back when.. Modern balers (from 'mid 60's forward anyway, might be earlier),put hay into "leafs" , with heavier bales having more leafs than lighter bales.