I'm planning on building an iron golem farm in Minecraft 1.8, and I want to know how far from my base it can be and still work. All the information I've found related to mob spawning deals with hostile mobs, e.g. the 24-block minimum distance for spawning and the 128-block despawn distance, but those rules don't apply to golems. I haven't found anything describing the distance at which the special village golem spawning happens.
I built a simple test golem farm in creative mode and found that at a distance of roughly 200 blocks taxicab, 140 Euclidean, it doesn't seem to work: I waited about 20 minutes and got no iron. But it works when I'm closer. I could probably determine the threshold distance through trial and error, but that's slow and unreliable (since golems spawn infrequently and irregularly), so I'm hoping someone knows what the actual rules are.