!Since you got great advice on broodiness and eggs, I'll fill in with colours. Unless your drake is split to Chocolate, you will get all blacks. If he is split you will get a mix of blacks and chocolates.
The white head is a dominant trait and only requires one copy of the gene to show. If they both have two copies, all the babies will be whitehead. If even one of them only has one copy, you'll get a mix of whitehead and solids.
Hope that helps!
