Minecraft wiki entry for Iron_golem_farming, associated text: Controlling the village center is often the most difficult part of designing, building, and maintaining an iron golem farm. The center is important because it determines where structures must be built to spawn, contain, and transport the iron golems. Iron golems can spawn in a 16×6×16 volume around the village center point; that is, 8 blocks in all horizontal directions from northwest bottom corner of the POI block, and 2 blocks above the top and 3 blocks below the bottom of the POI block. To protect against center shifting and also capture all available iron golem spawn attempts, farm designs commonly cluster beds at the center of the farm and have the spawn platform(s) extend 8 blocks out from the furthest bed pillows in each direction.