Put the summary of the bug you're having here

What I expected to happen was...: The game not crashing?
Describe what you thought should happen here: Nothing unusual.

What actually happened was...: Game / java crashed
Describe what happened here I was modifying my Iron farm. I had previously built a Villager breeder over 80 blocks away (separate village), and used an aqueduct to bring Villagers to a new holding area by the Iron farm. I was culling villagers from the old holding pen, and modifying the pen with Jack-O-Lanterns in preparation to turn it into more wheat farmland. Game crashed during that process.

Of note: I do have an automated Pumpkin farm right next to the Iron farm, that uses Sticky Pistons to harvest the Pumpkins at regular intervals based upon a dual slaved Hopper clock.