I still think it's not sustainable to wait that long, I believe the best rout to take is to feed restrict a few males, they mature fast and should be mounting the hens about 5 month old, cross them to dual purpose breed hens that start laying around 18-22 weeks of age, the cross is terminal, that is what "Premium" Labels are doing now.My main goal is to hatch and raise my own meat birds. I don’t really care about how late she or her babies lay.
For example the Bell & Evans Premium brand is a regular Broiler Males crossed with Dual Purpose Hens.