I only hatch from the darkest eggs and feather legged too but it does not seem to carry 100% on any of the varieties.
Did you use a Wheaten in your line? There was much debate about it on another thread. I always thought to use the Black Copper X Cuckoo. Wheaten would be nearly impossible to get to breed true if bred into GC. BUT if a peson unknowingly used a line of BCM that had wheaten hidden somewhere....... You never know what you will get. I had that problem last year. I spent most of the summer trying to figure out what I really had.
I noticed the crow wing is golden on your younger ones in the top, that was why I asked about the wheaten.
No, it's not the wheaten they are carrying it's the gold duckwing (aka salmon). From my original hatch I had what I thought was wheaten only later to discover he was duckwing. I sold him but he is still local.