For a Black Star hen and a Barred Rock rooster, you should expect all chicks to be barred, but they should have the darker barring usually seen on Barred Rock hens. Some will be nicely black with barring, some may have red, white, or yellow peeking through in patches (like what Black Stars have, or sometimes a white form of the same.)
If you raised them from chicks: did either of them take a really long time to grow their feathers?
You will not be able to sex them by head spot, or by barring, or by gold/silver. If the parents both grew their feathers at a normal rate, then you will not be able to feather-sex the chicks either.
Unless you know how to vent-sex chicks, I think you will just have to wait until the males start showing bigger, redder combs and wattles than the females. That usually happens somewhere between 3 and 8 weeks old, although both earlier and later are possible. Or you can wait longer, until you see pointy saddle feathers on the males. Of course, crowing is also a fine sign of being male.
