There are many, many factors to consider when culling other than color of the feathers. Type should be the foremost consideration. Look for a well balanced bird, full fairly deep breasts, 40 to 45 degree tail angle, tail neither too long nor too short, color of eyes (especially a problem in blacks and blues), and yes the EGG color. I use a double fault method of culling. I will accept one major fault in a breeder as long as I have a mate to compensate for that fault - as Michael recommended. Two major faults and out they go. There is enough decent black and blue stock available that you should not have to tolerate black or dark brown eyes AND green eggs AND/OR poor shape, etc.