I had that happen one winter, it was a really bad winter, so they were penned up quite a bit, and there was a very mean New Hampshire Red who was pecking everyone's backs, just above the tail, bald! She of course, had all her feathers! I gave her away to a friend who had a larger farm.
I do think they do this when they're bored, or over crowded. This makes them grouchy and mean. My flock is used to free ranging alot, and in the winter, they are definitely more penned up. So I make sure I don't have too many hens. It seems like in the spring, I'm always excited to hatch chicks, then I have too many and have to rehome some......I'm resolving myself to keep the ones I've got next spring and no new chickens for a few years.......Ugh, that'll be hard.....LOL
It really does help to have things for the chickens to do during the winter months. I put tarps around my chicken run to block the wind, and I throw some flakes of straw in ther for them to kick around, and I'll give them a cabbage, or a flock block. You can buy them bunches of greens like kale at the grocery store and they just love that.
And naturally cracked corn or scratch before bedtime helps bring up their body temps during the night, when it's colder. In the fall, I will rake up some leaves and throw them into the run because they love scratching in different things.....