You can guess that the pullet will start laying when her comb is bright red. She may start to squat when you try to pet her or sit in the nest box for a time. The time when she starts to lay can vary even within the same breed. My White Leghorn started laying at 19 weeks - but another poster has a WL and she's still not laying at 24 weeks. So, it can really vary. My EEs started at 21 weeks old and would sit in the nest box for about 3 days off and on before they actually started to lay. If there's a rooster - the rooster will start mating her as she gets close to laying. Sorry, not much help. But the 16 week time frame is really less realistic then the 22 week that an earlier poster mentioned. I have one that's 22 weeks old and still hasn't started laying.