How do I store hay properly to preserve quality and prevent waste?

Proper hay storage is a significant economic and nutritional management decision at any horse facility, because hay stored incorrectly — exposed to moisture, stacked on bare ground, or packed too tightly without air circulation — will mold, heat, and lose nutritional quality. Moldy hay can cause respiratory problems and digestive upset, and heat-damaged hay loses the protein and energy content that gives it feeding value. The most critical factor in hay storage is keeping moisture away from the hay. Hay that enters storage with excessive moisture content will heat and potentially mold as it continues to dry in storage. Hay should be tested or dried adequately before storage in enclosed spaces, particularly for large quantities stored in enclosed barns where internal heat has nowhere to escape. Ground contact allows moisture to wick up into the bottom bales of a stack. Storing hay on pallets, railroad ties, or other materials that elevate the bottom layer off bare ground or concrete prevents this wicking and maintains the quality of bales that would otherwise be lost to ground moisture. Air circulation within the stack is important for hay that enters storage with any residual moisture and for maintaining quality in humid climates where ambient moisture can be absorbed. Leaving spaces between stacks or using storage buildings with open sides or adequate ventilation maintains the air movement that prevents moisture accumulation.