One of my 8 month old Buff Orpingtons just finished with her first broody spell. She relentlessly sat on the nest for two weeks, only coming off once or twice a day for a quick bite to eat. At first, she did not squawk, growl, or fluff up. After about four days, she began the classic broody behavior. The extreme cold snap broke the broodiness, and she went back to her normal self. All of my chickens have laid soft shelled, odd shaped, or small eggs when just starting out. Anyway, just keep an eye on her. If her condition changes, or she develops any type of other "symptoms", then I would think something might be wrong. -hope she perks up soon!