Hi, i'm new here. My first generation villagers died today (all besides 1). They died while i hadn't the program running, and now their skeletons are scattered through my village. How long will it take that those bones dissapear?

They will usually disappear in about a day. Once your villagers advance a bit more in their knowledge (Village Tech), they will be able to provide a proper burial for those who die.

When you quite the came to leave it for several hours either pause it or put on half speed. I leave mine on half speed when I'm at work or over night; unless I'm working a hard game. On a hard game I pause it because you have to stay on top of everything.