BC, maybe I said this already... But you might be able to get your booty and stay put if you put food and water as close as possible if not right in the nest box with her
Food would be possible but not water, my coop isn't heated beside a single heat light in case they need it. Plus I think other girls like to sit right with her, trick her to sitting on additional eggs which is when she leaves the box. I had to pencil numbers on the eggs to know which ones the original 5 (4) are.