She looks like a white rock to me as well. This is mine, a late spring hatch. This picture was taken in October. Her comb, wattles and ear lores have matured and she's laying now.
I was just in the coop and tried to get a new pic of Opal, my white rock. As raisins were in the offing, no one wanted to hold still for a picture. This is ~ 2 months after the other one I posted