I have 3 Buff Orps, they are 22 weeks old. The BR's of the same age started laying last week. My other hens all started between 18-22 weeks. Only one of the Orp's looks like she is ready, comb getting red and bigger.... yet she hasn't even been interested in the nest boxes or hasn't squatted... just curious. No complaints as I am getting between 11 and 12 eggs a day from my others.