Founded in 1982, Old Mill Farm and Ranch Supply provides a multitude of services for local farmers in Belen, NM and beyond. Family owned and operated, we offer seed, fertilizer, food for farm animals and pets, gardening tools, western wear, stock and propane tanks, and so much more. Founded in 1982, Old Mill Farm and Ranch Supply provides a multitude of services for local farmers in Belen, NM and beyond. Family owned and operated, we offer seed, fertilizer, food for farm animals and pets, gardening tools, western wear, stock and propane tanks, and so much more.