My friend has 6 chickens, she had 7, one recently died. My guess is that they have vitamin A deficiency. So I'm curious as to how they would get that if they eat layers feed and scrapes from the home. They often get blood spots in their eggs, (they've been laying for over a year now so it should be rare at this point), and one of them has pretty jacked up feet (scaly mite leg) so I can only assume they all have it now since I saw this a few months ago. So My guess is both of these causes is from lack of vitamin A. I will be taking her chickens, quarantining them, and treating them. Hopefully it's not too late, but I think one of her chickens died from scaly leg mite? Even though her legs seemed fine to me, but she was losing feathers. The other chickens also law maybe 1 egg a week, I live in WA and it's been 40-50 degrees here. My 3 month old chicks sleep outside, it's warm enough for them.