One of my chickens won't get off the nest and it has been there for about a week now. I can't tell if it is laying eggs or not because the other chickens in the coop just jump into the same nest box as it and lay an egg then leave. Also i tried taking the chicken out of the coop and closing the door so it couldn't get back in but it just hung around just outside the door and stared at the coop. She will only leave the nest to eat and drink then goes right back. Also when I get close she makes this horrible screeching noise that I didn't even know was possible for a chicken to make. At first when i realized that she wouldn't leave I just figured that she would eventually realise that her eggs wouldn't hatch and leave but I am starting to get concerned. What does this mean? Is this called being broody? When will she stop? Is there anything I can do? Any help is much appreciated, thanks.