Exactly Diddle! I'm old school and believe that a hay bale needs to breath after baling.They sell here to guys who bale a lot of straw for mushroom farms. Gets the weight up on their trucks and reduces the amount of bales, as they're paid per tonne, not by the bale. Local contractor even bought a steamer to help build bale weight of straw after combining. Other than that, they're dangerous in my opinion for normal hay as moisture becomes even more critical to have exactly right. And when does that ever happen ??