If you put a non-barred rooster (and non-dominant white) over a barred rock, you'll get a black sex link. I don't think most Icelandics carry barring. You can clearly see saddle feathers on the barred birds in the pics, not the specific birds the OP is asking about as they've apparently already identified them as males.I am pretty sure they are all pullets. Icelandics are rainbow chickens and dont have a certified color so there is no way they make sex links.