About the underside of feathers - I think it's normal. I've seen the same thing on my BC, and on a lot of the other colors the underside of the wings is different than the side that shows.
I've never read anything about genes that affect the underside of feathers, and have not seen any faults or DQ's based on the underside color of feathers.
I've never read anything about genes that affect the underside of feathers, and have not seen any faults or DQ's based on the underside color of feathers.