You should absolutely use blacks that have come from blues if you are going to breed a black to a blue. But there are lines of "true blacks" that have intentionally been bred with the "gold" or "red" gene to enhance the black and these should not be used in breeding blues. I'm not sure if everyone understands what I mean. I got some "true blacks" from HinkJC a few years ago. The beetle green shine was definitely more pronounced than that of a black from blues.
Here is young George at 8 months. My plan was to breed him to blues but then I learned of the difference and didn't do it. He is a true black. It was impossible to
not have the green sheen show up like this unless he was in deep shade.
Now that I think of it, this shot was taken in the shade. Not deep deep shade but shade anyway, no sunlight is directly hitting him here.
As you can see, the sheen is green, almost no purple to it at all. Purple in the sheen is not desired in a "true black." But will show in a black that came from breeding blues. And it's nothing to worry about in that case really IMO, it just means there isn't much or any of the "red" gene in there which is good if you're breeding blues.
By breeding only those blues that do not have red leakage it is entirely possible to breed it out.
I want to clarify that I am no expert at breeding blues. But I did once upon a time want to do it and gathered lots of information on the topic. I gave away my blues when I moved to the country 2 months ago and now only have buffs, albeit 3 are hatchery birds. They're my old girls that I can't bear to part with.
