i started raising chickens on 2009.i have added more breeds each year and have all purebreds in their own pens. i thoroughly enjoy this and meeting all kinds of people.i have bought hatching eggs and hatched and sold chicks and eggs.i have had very good luck with my birds and have all but 3-4 original birds from 09.i hatched a few Easter/olive eggers just to see what they would be and a few under a broody just to check fertility. of my original birds tho i have somehow forgotten to hatch my replacers.of the ones i am talking about are my Plymouth rocks-blue,silver penciled and partridge-all non-hatchery stock i think since i have all my original birds i just never thought of doing it yet but someone said to me the other day "wow, you have had those a long time".i thought" just 3 years" so it got me thinking. so my question is when do you start hatching replacements for egg layers? how many do you do at a time? i know this is relative to space and breeds but just wanted some other views.