Those breeds usually start laying between 20 and 24 weeks old. It's a rare occurrence when they lay earlier than that. Just a few more weeks, and you will be over run with eggs.
If the nest boxes are higher than the roost, then that is where they will roost. They instinctively will find the highest spot to roost. Roosts need to be about a foot away from walls, and should be wide enough for their feet to be mostly flat.
19 weeks is still pretty early for egg laying. Make...