So, a White Chantecler roo x Silver-Laced Wyandotte hen mix for Mouche? But then, where would the lack of weight come from? Her parents are big birds, and she's twice lighter than them.
I’m not sure about the weight, but rereading your post, she could definitely be a commercial layer mix, too, which tend to be lighter. I didn’t think barred rock was right because barred rocks are black under their barring, and solid black (aka “extended black”) tends to be very dominant in crosses.
If we knew which commercial hens went with Mouche's father, it'd be easier to get an idea of her plumage inheritance lol.
The white chantecler that was Carmen’s father was recessive white, which is not responsible for her coloring as she only got one copy of the gene. So you don’t need a white rooster, you need a silver one (her father must have been silver under his recessive white). The neck patterns and black tail are mostly due to columbian. Mahogany and autosomal red are often combined in breeds with rich red/gold colors, so you wouldn’t need to breed them in separately. The difficult part is keeping the rich red color when you cross to a chicken with the silver gene, as silver chickens rarely have autosomal red or mahogany. Two breeds that have those two genes (plus columbian) are Rhode Island reds and speckled sussex. Red sex links tend to have them, too, since they’re often RIR crosses. (But they also have dominant white, which lightens the color and gets rid of black.)
