I don't remember much of duck ownership in NY as a kid. I do recall a friend with a pond taking them for the winter though. I grew up in NY and prior to moving here to Alabama, I lived in Alaska. One of the chickens (polish) refuses to sleep in the coop. She uses the rail around the garden to fly herself up into a tree in the yard. Getting her out of the tree is not an option - she's up there. What point temp wise do I need to worry about her sleeping in the tree instead of in the coop?