Got these today. The rooster someone said could be a cross between a Barred Plymouth and a Barred Pencil. Here are some of the chicks, several of the black with silver "sort of" stripes have the white spot on top of the head. Any idea if this is a good indicator of cockerel or pullet? There are 10 that are black that have the pretty silverish looking stripes 2 are very much not black at all. She said they are about 3 weeks old. Thanks!