[chicken rocket]

Hi All, I'm after some advice...
We have 3 ex-Batt Warrens, we got them 9 months ago. Recently one of them has started sort of whining and sounding her alarm call at about 6.30 AM. The only way to stop her seems to let her out of the pen (already large) into the garden. Is there any reason she would change? any advice for stopping or delaying her. Already blocked the light out of the coup..... Neighbours would be very greatfull....