I got a mystery chicken from a local hatchery who said they received this free with one of their chick orders. It was all black up until about a week ago (roughly at 4 weeks) it started getting brown on its neck. I can't fully tell if it has a pea comb or a single comb coming in. Any ideas at what breed I have here? I've been suggested Black Sex Link, Copper Maran and Olive Egger.