I have 9 barred rocks that are 24 weeks old...two have begun laying and the rest aren't. The two that are laying began on the 13 of January and of course they are just small pullet eggs. Got to thinking about how I can enusure that I will have a constant supply of eggs. What is the normal production time frame for layers...two years? I am trying to decide how many and when to cull and when to purchase replacement chicks?