I have four 10 - 11 week old ducks, that think they have to sleep outside in the run. It's getting kind of cold out and I'm getting tired of having to go outside and make them go in for the night. Should I let them stay outside or keep making them go inside? Once I make them go in they seem to stay inside and not come back out until morning. I know ducks are usually fine outside at night in their run. But I don't know if they are old enough to be out there? Any help would be greatly appreciated! Thanks!