Automatic farming: pigs break crops

Pigs should uproot crops like potatoes and carrots, reverting the crop block to its initial growth state. The food item will be left on the ground, to be picked up or despawn. This would add an incentive for players to protect their farms, however industrious players would be able to harness this mechanic to create automatic farms, in a much more humane way than it is currently done with villagers. This reflects real life pig behavior, and is similar to a mechanic already in the game with rabbits. It could be disabled with the mob griefing gamerule.