A long winter's hay bill is decided in autumn, by arithmetic rather than optimism. Planning forage stocks means working out what the herd will actually eat between the first frost-driven night in and the spring grass, storing that amount so it stays worth eating, and noticing early if the pile is shrinking faster than the plan.
Start with mouths, not with bales
Work from each animal's weighed daily ration. A horse in winter typically eats forage at around two percent of his bodyweight a day, so use the weigh tape on every horse and pony, jot down each daily amount, and add them into one herd total per day and per week. Ponies and very good doers come in below the horse figure, which is exactly why the sum should be built animal by animal rather than guessed per bale. Include the days when poor weather keeps everyone in and eating hay around the clock, not just the average day.
Turn the daily figure into a winter total
Multiply the weekly total by the number of weeks you expect to feed forage before grass takes over, and plan for the longer version of your local winter rather than the mild one you hope for. Then add a genuine margin on top: some bales will be damaged, dusty or refused, doors get left open to the rain, and spring sometimes arrives late. Buying by weight wherever possible protects you, because bales vary hugely in density; a winter bought as a count of light bales can quietly be a fifth short of the forage you planned.
Storage decides what the stock is worth
Hay stored damp, on bare earth or under a leaking roof loses feed value and grows mould, so stack it off the ground on pallets, under cover, with air able to move around the stack. Rotate as you use it, feeding the bales most at risk first and keeping the best-sheltered for late winter. Check stored bales as the season goes on: a musty smell, white dust or heat inside a bale means it should not be fed, however tight the stock looks on paper. If part of the stock is wrapped forage, store the bales where the wrap cannot be torn by stock or machinery, use them in strict rotation once opened, and count them separately, since a punctured bale spoils rather than keeps.
Check the pile against the plan monthly
Once a month, count what remains and compare it honestly with the weeks still to run. Running ahead of plan is a pleasant problem; running behind it is only manageable if you spot it while suppliers still have stock and before prices harden in late winter. Keeping each horse's daily ration and the running stock total in his KinsLe Pet Passport records means the plan, the weigh-tape figures and the reorder point all sit together when you make the call.