Once the days shorten, you may not get eggs from your younger females if they haven't started laying yet. My pullets, if they haven't started by now, often won't until the day's start getting longer again ( spring) both my chickens and turkeys are mostly shut down right now, except for a handful of pullets that started laying a few months ago. The old hens molt out this time of year, and won't start again sometimes until spring or until I provide artificial light if I must get them producing eggs(breeding season starts in February for me so I can have chicks by March. March pullets will start laying before winter, usually.)