I think the chick on the left has good buff of a good medium shade.Females tend to run a shade lighter and Buff Leghorns seem to show less buff under color than other buffs perhaps because of the tight feather,however I sometimes get good buff under color.Males tend to have more under color than females,the darker buff show more quill and under color both sexes..Dark buff can show two shades and be uneven ,but sometimes light birds can too.I try not to mate extremes together unless you can spend several generations gradually remating to get back to an blended tone.I do find the dark buff more useful and the light and ty to keep a few darker buffs around.