The smell is strongest on this side of the house. After it rains you can smell coming in the windows.
What do you think maybe it was the neighbors septic? You can see the spot on the grass about 3 feet infront of the shack. That house has very little renovations, only the metal roof, that is filled with birds. How can sewage end up on the side of the house, maybe drained their i guess. Maybe he just didn't ever get a pump out?