I think I may have been confusing by talking about both projects in the same message.
I have:
1 x silver cuckoo cock
1 x silver cuckoo hen
dark cuckoo hens
black copper hens
1 x blue copper hen (Chanel)
My main project is the Golden cuckoo project. Crossing the silver cuckoo cock to the BCM hens will get the F1s. I know they wouldn’t be perfect straight away, especially the hens as they will be silver. But using the resulting S/s+, B/b+ cockerel over the silver cuckoo hens should throw some double barred, S/s+ cockerels, and breeding him to black coppers should get some pure gold, single barred cockerels. And half of the hens will be golden cuckoos.
If I used the dark cuckoos, it would be experimental and I know it would take a few generations to breed out the E allele.
My other idea was a project, to get more dark cuckoos, breeding the silver cock to the dark hens, then test mate future progeny to breed out any birchen alleles, so they are E/E.
Feel free to point out problems I’ve missed, I struggled to follow which one you meant here, but I think that’s my fault.
Thanks!