Hello, new here and researching to build my own coop as soon as the weather gets better. Design I'm working on has the 3x6 coop attached inside a 6x10 enclosure. My question is whether to door from the coop to the enclosed run should be open all the time or if it should be closed at night (keeping the chickens in the coop) and opened every morning? My proprrty borders a wooded park, so predators are a big concern. Also, is there a better material to build the coop with, to keep them warm over winter (currently negative right now, but rare to get negative double digits here)? Should I use some kind of insulating material or will they stay warm enough? Thanks so much!