I have not updated yet, but will do so and let you know. My friend had to actually set most the village on fire just to kill them as they were totally lagging him, and couldn't kill them all. Looks like this bug has happened in previous snapshots.
Breaking the skull and re placing it fixed the problem.
BTW, no one spawned them. Not possible, we live around 100,000 X and Z where as most of the server is closer to 20k. Also it is a very small server with probably 10 people on at the most and we all pretty much know what's going on at all times.