I have a compact (3x3x3 feet) coop with a small door that I close at night, and a sliding plexiglass window (1x1 foot) with screen on the side of the coop. Otherwise, there is no ventilation. I have read that this is essential for health. (We lost a bird to sudden death last week, so I'm considering all possible causes). If I have the window slid open 2 inches in the winter, is that enough ventilation? If I want to remedy this problem, does anyone have any suggestions? I am trying to avoid having to take apart the house. It has a traditional upside down "V" roof line that overhangs a few inches. If I drill a few 2 inch holes along the top under the overhang and then cover the holes on the inside with wire, would this do the trick and keep mice/birds/predators out? Any advice would be helpful!