You feed the birds so you decide what you want in your flock...I want to show mine and have dark eggs so I cull according to my vision. In my mixing of birds who are from different lines I try to choose the closest to the SOP and I want the darkest eggs so if they don't lay a 4 they are gone no matter how pretty...if they are not close to the standard but lay dark I have people waiting for them who have no plans on breeding them just want eating eggs. I have a waiting list for my culls and love sharing birds with other breeders who are trying to improve what we have to work with. You never know when a tragedy might happen so having birds closely related to your stock makes much easier to keep working on improvement if you loose some birds at least you know the faults. I've found that a master breeder will have better stock than just a breeder make sure you buy a SOP and learn what it has in it. Many problems people have is from not knowing the standard DQ's are DQ's no matter what the breed and faults are faults if breeding birds was easy there would be plenty of perfect birds to start with.....just saying make sure you are having fun