My 3 year old black rock molted a couple of months ago. Her feathers grew back as usual apart from the one's on her head. She looks like a vulture/chicken cross. Anyone have any ideas why? She's the oldest in the coop (4 other hens) and still the dominant one. We don't have a cockerel, and she's not fighting the others. They all have full run of a large garden during the day and she acts just fine. She doesn't lay much but that's nothing new - has always been a bit of a prima donna.

Any suggestions for feather regrowth appreciated!

thanks