Villager leaves house during night

A normal village with aprox 10 villagers. 4 or 5 farms.
Two nights in a row I have seen villagers leave their houses to go and check/harvest stuff from the farms. It possible that wheat and potatos grow to final stage since I'v added some torches here and there.

I'v also notice that a zombie can hir through the doors if I or a villager is standing very close to the door.

I'v also seen a baby zombie spawn inside a rather dark house. (this could have been a normal villager killed through the door).

I can see one villager standing inside a small house without closing the door.

I'v seen one villager getting killed during night running around like a headless chicken with several nice houses around him.