Exchequer Leghorns are very good layers of large, white eggs, almost as good as the production WLs. Some strains of single comb light brown Leghorns (I have one exhibition strain) are also superior layers of a nice size egg while others are pretty poor performers and lay smaller eggs even though they are of gorgeous exhibition quality. My WL/Norwegian Jaer crosses are my best layers.
As for the bias against WLs, I find that it is the reverse when it comes to showing. It is very, very difficult for a colored bird to compete against a white one, despite the fact that the Standard of Perfection has a different point spread to allow for the handicap of the colored ones (the white having more points for some other features and less for color). At times, I felt that the whites were unfairly placed ahead of the colored ones, and some breeders, I suspect, decide to breed the white varieties because it's easier to win with them by concentrating on "type" without having to worry about color and the challenges associated with color breeding.
Preference for white or brown eggshell color depended on the region, according to some of my old poultry books. Recently, the market for the exotic eggshell colors has reflected the newer fads: very dark brown shell color, speckled brown, green, blue, olive etc. The backyard breeders probably respond to these trends, and thus the WLs end up on the back burner though their production value (of any pure breed) cannot be surpassed.
