We have 6 hens that have been laying for 6 weeks--or I should say some have been laying for 6 weeks. They are 2 each of red cross, buff orpington and barred rock. We suspect only three are laying as we get 2 eggs in the same box, one in another (same box) daily. We've had a consistent 3 eggs/day for a month, never more. They were all hatched and picked up on the same day, May 2 of this year. Any way we can check which are laying or why the others aren't?