I didn't think it was too many.You always post too many pictures. It's hard to pick any single image to respond to.
Mosaics are not an officially recognized breed, but there are a group of breeders working towards that goal. They shouldn't be bred any which way and still use the name.
Mosaics must have blue ears. But blue ears don't make a Mosaic (Silkies, etc.).
The feathers should be patterned with white - the exact look is still in flux.
They have green legs. Blue skin. Blue beaks. Small straight combs.
Fibro is interesting to work with. I have some homebred fibro eggers that came out dark as night everywhere from Mosaic x Black Ams. Kinda cool. Also lots of sheen, reinforcing the idea that ACs were used heavily in Mosaics.
I would hazard a guess that the question askers hen is AC x Leghorn, based on the heterozygous dominant white, and the strong fibro expression.
Mosaics are still new to me, still learning. Any information is appreciated.
My first thought when you initially posted this chick was blue gold birchen as well. My experience with Black Copper Marans, a gold birchen based variety, was that some would get this mossy, rusty color throughout their juvenile feathering that would make them look almost brownish, so I wonder if that's what you're seeing in this little one. It always molted out and was replaced with the expected birchen patterning by adulthood.
