Blue x Mille Fleur throwing black copper chicks?

[slantrhymes]

Hi! I have a question for the genetics gurus here.

I have two hatchery chickens: a Blue Andalusian rooster and a mille fleur Barbu d'Uccle hen. We hatched their eggs this year, and, based on the chicken calculator, we expected to get blue and black solid-colored chicks.

We did get two black chicks, but recently (at about 4 weeks of age) one of them developed copper on its neck.

Now, the rooster has significant gold/red color leakage. I've been trying to figure out what genes might control it. Now that one of his chicks has this unexpected coloration, I'm hoping it might be possible to solve the mystery.

Is it s+/s+? Mh? What do you think?


Thank you for any ideas or help!

 

[nicalandia]

a birchen like pattern can be expected on such cross due to the heterogeneous nature of the resulting offsprings, you can see that on black sexlinks hes too(hens look brown red which is the gold version of birchen)

Black Sex link rooster(take out the sex linked barring and you get a birchen like pattern)

Black Sexlinks: https://www.cacklehatchery.com/black-sex-links.html