If she does decide to sit... you should be fine in the coop unless there is a hen who routinely bothers her. My only suggestion would be that once she decides to sit you should make sure she has all the eggs you want her to hatch on the same day and mark them. Then any eggs added to the clutch by other hens laying in her box you will know they are new ones and can remove them to prevent a staggered hatch.and apparently it was a false alarm, after sitting on her nest and growling for about six hours or so, she hopped off & hasn't been back on since. but perhaps this is a sign of impending broodiness?