In that case, the sons should have white barring and the daughters will not have the white barring.
There is a chance of the sons hatching with a light spot on their head (caused by the barring gene), but I think it is more likely that they will all look alike at hatch.
When they start growing feathers, you will probably be able to see white lines across the feathers on the males (barring) and not on the females. The white lines will be more obvious on black feathers, which probably will include the big primary feathers that grow first in the wings. I think you will probably be able to tell within the first 1-3 weeks, which is faster than waiting for the males to grow big red combs.
