How much hay storage do I need? 

A horse on a diet of strictly hay (no pasture) can consume between 2 to 4 tons of hay per year depending on their size, temperament and workload. A ton of hay needs approximately 230 cubic feet of space, depending on its density. Alfalfa, for example, is denser and heavier than oat hay, so it may require less space than oat hay. Grass or timothy is somewhere in between.

Start with how many horses you are going to feed per year and how many times a year you will want to buy hay. Then calculate the total tons you will need room for at any one time. If you are storing it in a loft you may only want to stack the hay to a height of 6’ (as high as you can reach). If you are storing hay in a separate building you may be able to stack the hay all the way to the roof.