Brrrr! This is my 1st year keeping chickens. I have 2 adults and one 7wks old in a hut -size about a 2ft6" cube. I've double-covered the roof to make 100% sure no wet can get in. There's 1/2" gap at top for air, and access is through a pophole, closed at night. Will they be alright? I'm used to indoor pets, and I'm not used to crawling into my cosy bed and leaving pets outside in minus 10deg. Except when we locked the dog out by accident, but that's another story! Any advice will be appreciated.