I have 2 buff orpingtons and 3 barred rocks who are all 25 weeks old, give or take a day or two depending on the chicken. I have yet to see an egg! I live in East Texas so they did their maturing during the hot summer. And I had coyotes rob me of 3 hens and 5 roosters just a few weeks ago. Could the heat and traumatic experience have led to delayed laying?