Understanding Double Barred Lemon Cuckoo Orps!! Anyone..

[MjChickens]

I just got some Lemon Cuckoo Orp chicks. And the gal told me that they could be double barred. I am trying to understand how this works and what I need to look for. Can anyone explain the double barring to me? Thanks for the advice, I hope that this is not a dumb question but I would like to understand it.

Also what is the true leg color for Lemon Cuckoo Orps. Yellow or Pink??