I built an outdoor wire pen for my drake and duck. It's covered and measures 6' x 9' with a 2' x 3' enclosed box at one end. It is safe from any predators. My ducks have never used the box which is lined in straw. The duck spends the entire night in a small tub filled with water and the drake stands on a rock next to the tub. I thought for sure they would want to "hide" in the box area at night! Anyone have any idea why?