What's Happening to Biscuit's Feathers?

[FreeChicken!]

Biscuit, my 3-year-old Buff Orpington hen, is starting to look nothing like a Buff Orpington. She's kind of skinny to begin with, but suddenly she's starting to look like she's falling to pieces. At first I thought it was just because of the roosters and mating and all that. But her feathers just keep falling apart, despite the fact that the roosters will hardly come within a foot of her anymore. Few chickens will, actually. That's how I know nobody's picking on her: Biscuit is actually the bully of the flock, chasing smaller hens around and snapping at the combs of larger hens. Whenever another hen is in her way, she either bites them or steps on them. So I know nobody's pulling out her feathers. Her feathers don't even look like they're getting pulled out or falling out. It seems that Biscuit's feathers are breaking and the broken pieces are falling off. The poor hen only has about three or four flight feathers left on each wing.
What's happening?

 

[chicmom]

Well, she's either having a terrible molt, or she has parasites. There are feather mites that actually eat feathers, maybe it's that. I would grab her at night because they're easy to catch when it's dark, and take her into the garage or where ever, with a light, and really look her over, right down to the skin. Sometimes they do catch parasites from wild birds......

 

[FreeChicken!]

Oh dear... Thank you, I'll check her tonight.

 

[FreeChicken!]

I don't see any mites on her. I checked thoroughly. So I guess the reason for her feather loss is still a mystery. Or maybe I can't see the mites?
Meanwhile, I'll keep giving her sunscreen while her feathers grow back.

 

[FreeChicken!]

I don't see any mites. Hmm...