Too many golems!

A friend and I have been playing a LAN server where we set up shop in a village and are fortifying and protecting it. Iron golems are, of course, a great asset in this regard, but not when they spawn endlessly! They do not seem to recognize when they hit their limit and continually spawn. I had to use the kill command to cut them down, and 50 entities were removed. Within a few minutes, we had ten more spawn.