Yes, that's alot clearer. What is F1The birchen pattern on which BCMs are based naturally codes for laced copper on the breast, but the BCM SOP calls for a solid black breast in hens. Therefore work is done in BCM lines to correct this that isn’t necessary in other patterns.
As a result, the F1s might have copper in their breast that shouldn’t be there.
I hope that makes sense. I can grab photos if it will help.
Yes pictures would be great