Thanks so much, reading nowI also enjoy reading old poultry books, things about genetics (even if sometimes I can't understand them), and so on. Heres an article you may like. I haven't finished reading it yet. I have read some, not the best article I have ever read, but it is interesting enough.
http://archive.org/stream/BreedingA.../BreedingCullingByHeadPoints#page/n0/mode/1up