It won't let me enlarge the picture. What color is the skin on their feet? They look like they could be Blue Australorps. The one darker chick looks a little different, do you have a full photo of it?
Blue Australorp, and the blues can come in different shades. If you are in AZ. most of the feed stores get their chick's from Pruitts Hatchery in N.M. and they do have the Blue Australorps. They have had them for over a year.