They can still be Sumatra, and that is what I am thinking they are. Any chicks can very from the common coloring. I have a wide variety of coloring on same breed chicks I have right now. Sometimes you see breeds you know will be all black on their feet and some on their beaks as well but it doesn't come with that as a chick although in time will turn black. I think you just got a really black Sumatra chick. Does Privett have them? I didn't know that Welp drop-shipped from them. That is good to know.