I love, love those dark brown eggs that come from the Welsummer. Spotted ones are cool too. I was going to get a couple of Welsummer hens this spring. Are the darker colored eggs higher in any nutrients than those of lighter colors?
"The colors of eggs come from pigments that are secreted by the hen and deposited on the eggshell's outer layers during formation in the chicken's oviduct, the canal that eggs travel through from the ovaries to the outside world. Egg color is a genetic trait, so colors vary from breed to breed. Brown eggshells contain the pigment protoporphyrin, a breakdown product of hemoglobin. Found only on the shell's surface, the brown pigment can be dissolved by vinegar or rubbed off with sandpaper. Blue and green hues are caused by the pigment oocyanin, a by-product of bile formation. White eggshells are devoid of these pigments."
So unless the break down products of hemoglobin or oocyanin are going to be good for you in some way, provided you eat the shell, the insides are all the same.