Another method of preventing mold development is to dry the hay in the barn. For example, one Illinois producer has developed a system of drying large round bales using a solar heat collector on the roof and side of his drying barn.
Any system for barn-drying small square bales would have to be of sufficient size to dry a large volume in a short time. A batch drying system is most successful if the bales can be moved in and out mechanically. This can be done with square bales by stacking them on pallets, six to eight bales high, and handling with a forklift.
To improve the drying efficiency, stack bales on edge and together tightly
so air flow moves through all the bales.