Spawn rate of iron golems seems to be very high. My village has at least 38 beds and villagers have been breeding nicely. Somehow the iron golems kept on spawning too. Not sure what causes it but the performance takes a big hit. For a while my villagers were in love but there were not enough beds. After a while I added new beds and villagers continued to breed. After working outside right next to my village for a few hours I came back to my town filled up with Iron golems.