I have seen many advertisements for egg laying hens, usually around 2 years old. The description usually mentions the advertiser is making room for new chickens -- so I wonder, when do chickens typically stop laying reliably? I want to replace 4 of our flock that turned out to be roos, but would it be wiser and more beneficial to wait until Spring to raise chicks another season? I'd hate to purchase laying hens only to get a short time out of them production-wise. Currently, my pullets (and one cockerel) are 20-21 weeks old. (No one's laying yet!) The hens I am thinking of purchasing are 2 years. I would be adding 4 hens to 5 pullets and 1 20-wk old Roo. I haven't seen any pattern as far as a "pecking order" being established. They're all quite docile, including Roo, and they squeeze together on the top roost. How's that sound for integrating?