Twisted 80s Horror Flick

I can't remember the name of this old 80s horror movie, but it was pretty twisted.

A group of people get lost in the woods and find an old cabin. The people that live there are a bunch of crazy hillbillies with a fat daughter and a deformed brother, and they have a dead decayed baby that sits at their dinner table with them.

The daughter takes one of the guys from the group to her room and makes him have sex with her in lieu of her killing him. But after they do it he pisses her off and she kills him by stabbing him in the eye with the pole from a carousel horse figurine.

That's all I can remember any of the other details but it was a messed up movie.