Hi I received 8 Light Sussex from a mixture of two different lines recently imported from Europe. They are now almost 1 month old. The 3 cockerels are growing the black hackle feathers and so is the one female, but the 4 others have not a lick of black in their hackles. Is this normal for some to be slower at growing the traditional black hackle feathers, or are these from a different breed? I already found out one is an American Bresse and not a Sussex so I wouldn't be surprised. The other 3 I am not sure of have white shanks