Planning ahead can go a long way when it comes to storing hay.
Barry Yaremcio, Beef and Forage Specialist with Alberta Agriculture and Forestry says, it's important to remember, where ever the bales touch and water gets in, spoilage will occur.
"Try to stack them in single rows, bales are six inches apart, and one right beside the other like a row of marshmallows. You don't want the bales to touch, because any place those bales touch when you get rain, or when show melts, that's where the mould starts to form and the deterioration occurs."
Facing the bales into the wind will allow the snow and moisture to blow off in the spring. If you are tarping your bales, leave the ends open to allow to wind to move through the stack to reduce moisture.
Having your bales covered is always preferred, but when they have to sit in the elements, Yaremcio suggests not stacking them. The less contact the bales have with each other, the less spoilage there will be.
"When the round bales have gone through a winter, or a bunch of weather damage, the digestibility of that hay will go done by roughly 10 percent. Your energy and protein contents in those bales will also be reduced, and the amount of feed the animals are willing to eat on a voluntary basis also drops by 10-15 percent."
Source : Steinbachonline