Minecraft wiki entry for Before_Village_%26_Pillage, associated text: Iron golems will spawn near the center of a village if it has at least ten villagers and 21 houses. Additional houses beyond the 21st will make no difference as far as golem spawning is concerned, although 29 would be needed to spawn ten villagers naturally. Additional villagers will allow more golems to spawn, in increments of one golem for every ten extra villagers (so 0-9 villagers allows no golems to spawn, the cap is set at zero; 10-19 raises that cap to one, 20-29 raises it to two, etc.). This cap only limits the number of golems in a village at any one time; as soon as one is killed or leaves the village boundaries, a new one can spawn in its place immediately.