Stack hay for farm animal sanctuary (physically demanding)

We need people who can drop hay down from our hay mau and bring it up a short ramp into our hay stall and stack it there. The stall holds about 50 bales, and we'd like to keep it full. Volunteers can come do as little or as much as they can. Ideally a team of 2-4 people can get the hay stall filled in less than an hour. This would be a weekly activity.