Once the younger girls are laying they'll make their way into the flock's social order.
Just one hen penned up with him in a confined area wouldn't be a good situation with a hormonal young cockerel. Either he'll harass her to distraction or she'll beat the tar out of him.
I'm getting a...
:caf
Because I have a 5-month-old cockerel I'm watching for his signs of maturity/taking on the role of flockmaster.
The other day I saw him round up a pullet who had strayed from the group.