Yeah, but this is where it gets weirder.
Post in thread 'Black To White Experiment' https://www.backyardchickens.com/threads/black-to-white-experiment.1545531/post-26466135
I have a large fowl Splash Cochin hen who actually gets feathers like that all the time! Any blue in their background?
I can't remember if I've saved back any of her feathers, I'll have to look in my feather collection. She is not cooperative for pictures so would be hard to get any pictures of feathers still attached to her.