It’s probably overmating, other birds picking on her, or her own feather picking. Keep a close eye though, because it can also be a sign of protein and/or other nutritional deficiency. You may be feeding your birds correctly, but if she’s getting picked on, they may keep her away from the food...
Certainly looks that way, I have 5 Salmon Faverolles chicks and all of their wing feathers are flat just like their parents. I have seen pictures of Frizzle Salmon Faverolles on the Official Faverolles of the USA page on Facebook. They also have a website. There is also an unofficial Faverolles...