Zombie siege

Sieges are an upcoming feature in Minecraft. The first part of the project was added in 12w07a. Currently, zombies have a chance of coming in to the village in packs and attacking the villagers at night. Usually, a whole pack will concentrate on one door or villager. Villager breeding will keep the population up. In the near future, villagers will have some type of mob used to defend them.

Trivia

 * When a zombie is attacking a villager or door, it usually cannot detect you.
 * Zombies also attack baby villagers.