2 questions: I was told that they will double up in a larger nest box to stay warm at night. Is that true? If so, I guess only some of our hens would be lucky to be in the boxes? Or is that just a myth? I'm building a double nest box, so it will be two boxes side by side. They will be bigger boxes, about a foot deep, foot high but 16" wide (for each individual box). Does that sound good for 9 full size hens?