We have 15 birds in our henhouse, one of the barred plymouth rocks is spending all her time in the nest box. It was one of the nest boxes that all the other ones like to use, (now they changed up and are using other nest boxes) as far as I can see she is just spending all her time in it all by herself. I cant tell if it is one of the new rocks or old ones. Is this normal behavior? The new ones might be getting ready to lay for the first time?