My bet is Isbar.
My thought is that they come into lay just a bit earlier than CL - and they have a greener egg. Game cam could help--- there are other methods too--- Best is if you an find her in the act -- or exiting the nest as the only one doing so - and the egg is still warm.
Good luck solving it -- I bet within the next 2-3 weeks you will get a more blue colored pullet bullet.
My thought is that they come into lay just a bit earlier than CL - and they have a greener egg. Game cam could help--- there are other methods too--- Best is if you an find her in the act -- or exiting the nest as the only one doing so - and the egg is still warm.
Good luck solving it -- I bet within the next 2-3 weeks you will get a more blue colored pullet bullet.