Are we talking 10% for patterned varieties( Columbian, wheaten, or anything along those lines ) or solid colors( excluding blue I would assume)?
Also to get lines that practically produce copies of the parents, how is that achieved? Obviously not adding a bunch of new blood would help but which breeding method? Would I just have to breed the crap out of them( e.g. many generations, not just a ton of chicks ) and keep my genetics close??
Rip is a judge, so he can answer better than I. All I can share is my own experience. Last year, in breeding some of the best Barred Rocks you might imagine, we put 70 chicks on the ground, give or take. Of those? We only kept 7 or 8 birds for our future breeding plans and might have shown only half of those, had we wanted to do so.
So, Rip's percentage is quite accurate in my view. The more skilled the breeder, the longer the line is bred the better your chances get for producing what I call a level produce. Walt Leonard mentioned last spring, I think, that he could have taken any number of his New Hamps to show. They were just that level. This isn't nearly often enough the case.