If you live in the top half of the planet, days are now getting too short to produce enough light to trigger the laying hormones. Your young ladies may be ready to lay eggs, but you may need to wait for January when the days will be getting longer.
The signs to watch for are reddening combs and crouching when you reach for them. Another thing you can check on is the pelvic bone knobs on each side of the vent. They will get farther apart as point of lay approaches. Right now you may not get more than one finger width between the knobs. When laying is imminent, you will be able to fit two fingers between the knobs.
When the day comes for the first egg, a pullet will act agitated, restless, and she will usually be very vocal and sound like she complaining about how the world is being run. She'll make a ritual out of surveying every inch of the coop and run for a suitable nest. Placing hard boiled eggs or fake eggs in the nests often help her get the idea that nest boxes are what she's looking for.
