It is a roo....and it is either a Barred Rock roo or a Black Sexlink roo...being what the others said...a black sexlink is a non-barred roo over a barred hen....the female chicks will hatch out black with some color bleed through from the father; the male chicks will looked barred like the mother as the mother determines sex.
Male black sex links will be barred, and often not as crisp as the barred hen, which is often a Barred Rock....so that is the only way this chick could be considered a "Black Sex Link".....if it is the male chick from the non-barred/barred mating.
Lady of McCamley