I'm not sure what the mix is, but the feed store said Australorp mix. About 5 weeks old and I noticed today the comb has some color and there are some wattles...isn't it a bit young for that if it's a pullet? Sorry this little one runs like the dickens from everyone so getting a picture is hard!
I'm a chicken rookie, but I would venture to guess s/he is a cock. I base my judgment on the tail feathers, but there are others on here that are probably much better judges.