15 weeks is a bit early for a pullet to be thinking about laying, but I have heard of some breeds starting at around 16+ weeks. What does her comb look like? If it starts turning bright red, it's a signal for the cockerel that she is approaching laying, or actively laying. (This occurs naturally, regardless of whether or not there is a male present). Her pelvis will be wider and if you look at her vent it will be moist and pink.
There is also a simple test you can do to check if your hen is laying/ getting ready to. Hold the hen firmly and turn her on her back. Put your fingers on her breast bone and work your way down to her vent area. You should feel 2 bones sticking up. These are her pelvic bones. If you can fit only 1 finger upright between her pelvic bones she's still roughly 4 weeks off laying, 1 and 1/2 fingers means she's a little closer, 2/3 weeks and 2 or more fingers means she's either close to or laying already.
That's a good visual, Sumi! I have had so many girls start at 17 weeks and so many that I didn't think would EVAH start that I have taken a "ho-hum" attitude. I know, I'm a complacent egg-waiter-forer.
Thanks @Blooie It's easier to show than try to explain sometimes. Hen was not very impressed though lol I've waited more than 8 months for an egg from a favourite hen once. And when she finally delivered, she laid it in my lounge, on the floor, a soft-shell egg. Scared the crud out of my DS's friend who was visiting at the time… Got to love chickens?
