Also, you can tell when your girls are really close by feeling their pelvic bones. Pick up your chicken, backwards; with their head facing behind you. Look for the vent. If its dry looking, they aren't ready. If it looks wide and moist, they're getting there. Then, put your fingers on either side of the vent and feel around for two bones poking out on either side. These are the pelvic bones. Just like women, wide bones means sexual maturity, or in this case; egg laying. Your looking for pelvic bones that are 3 finger widths apart. Once your there, the girls are ready to push out those eggs.