White Rock hens are 6 months old and not laying!

[My peeps]

I have 8 white rock hens, 2 leghorn hens and one rooster. My leghorns are over a year and lay almost everyday. My white rocks are 6 months old and still aren't laying. They are no longer free ranging (too many predators) so I know they aren't hiding their eggs elsewhere. Is this normal?

 

[cypressdrake]

I had some white rocks that went close to 7 months before they started. Sometimes they'll start later then others. They will lay, just not always when we expect.

 

[Peplers chicks]

Do not worry, some chicks takes up to 8 month's, and according to me, the longer they takes the better is the quality