 Depending on the size of the field and the amount of hay produced per acre, once a beaverslide has created a stack, it can be moved a few feet to make a long, continuous haystack, or moved a longer distance to create multiple stacks within a field.Many are built on skids to facilitate being moved from field to field.If the hay is stacked properly, and remains uneaten, the hay in a beaverslide-constructed stack remains good at least two to three years, with some ranchers claiming it could last up to five or six years.