I am not sure how you are taking danceinchicken's reply to impy ANYTHING about diet.
Danceinchicken commented that it "almost looked like" the chicken had been "inked". This is something that hatcheries/breeders occasionally do to tell different chickens apart (cockerels from pullets, most often). It has nothing to do with diet.
Furthermore, danceinchicken observed that yours had greater comb development than average for that age. Again, this does not point to a dietary deficiency. Dietary deficiencies result in slower growth. It could be that your bird is actually a cockerel, was inked, but someone made a mistake sorting. It could be that your bird is indeed a pullet, and she just has some nonstandard genetics - when I was fostering my neighbor's GLWs as pullets, we had one that had a comb at the same age as yours - my daughter was hopeful (!) that it was a rooster, but it just turned out that the girl is not true to breed: she has a regular comb, not a pea comb. Clearly not show quality, but hey, she lays eggs, and lays them where she's supposed to.