Mimi, I don't pluck feathers. When any of them start getting a little bare, I separate. New feathers grow in. No plucking needed. I don't usually have to separate more than twice a year, and one of those times is for molt. BUT it wasn't always that way.
When I first started with chickens, I was doing pretty good with them, so the following spring, I decided to add to my flock. I bought 2 red sex-link pullets, one older than the other. The older one had just started laying. She had been way overbred, and had a serious case of bare back when I got her. Both of the pullets needed worming. YES, I quarantine. I dusted, wormed them, and got them in good shape during the 30 days. I introduced them into the flock, and things were fine. In short order, the one pullet was bare backed again. None of the others were having the problem, but I confined the rooster. She feathered in some, and once again the rooster was back with his flock. Again, she was bare back within a short time. I watched, and she was NOT being bred any more than the others, but she had very poor feather quality.
In the fall, when all the hens went into molt, this one hen went totally bald overnight. She looked like I had tossed her in a chicken plucker. From that time on, she was called Baldie. I put Baldie in a dog crate on the back porch. She couldn't be out in the sun, and with the other chickens in her condition. When I went to get feed, I bought a bag of Manna Pro Gamebird/Showbird feed. Someone suggested canned cat food, or canned Mackerel too, since they do need some animal protein. I was amazed at the results. Within a short time, she looked like a pin cushion. She couldn't be out in the sun yet, but had the run of the entire screened in porch during the day, then was secured into the crate at night. I used a wide putty knife, and would scrape up everything each evening. There was a drain, so every few days, I would spread some soap around, wet it with the hose, use the broom to scrub it, then rinse it all down. It took time, but when her feathers finally all grew back in, they were beautiful, and had a great sheen. Protein that high will affect their laying, so be sure to begin mixing the high protein feed in with regular feed, decreasing the protein, until they're back on regular feed.
The time had come to put Baldie back in with her flock. I was expecting her to be bare back in a short time, but to my surprise, her feathers were strong. Not only that, but the following year when she went into molt, she had a normal molt. She did not lose all her feathers at once. She was 5 years old when she died, had good feather quality the rest of her years, and was never bald again.