My hen is suddenly losing an extreme amount of feathers — is this molting?

Since this morning, I noticed a surprisingly large number of feathers lying around in my chicken coop. At first, I thought maybe a predator had attacked or scared the hen, causing her to panic and run around and lose some feathers.

But I just checked her again, and it seems much more extreme than that. She is literally losing feathers just from walking around. It looks like with almost every few steps, around 10–20 feathers are falling off.

She is becoming almost completely bald. Most of the feathers underneath her body have already fallen out, and only a relatively small number of feathers are left on top. Even those seem extremely loose — if I gently run my hand over her feathers, I can end up with a bunch of feathers in my hand.

What could cause this? Is this molting? Can normal molting happen this suddenly and at such an extreme level?

Has anyone seen a hen lose feathers this rapidly? I’d really appreciate any advice or explanation.