I agree, this therapy is very impractical to do specifically since most of us have plenty of other things to do, but I just got a chance to try it out on one of my other chickens, and it worked!
I was in the run checking on the water and fermented feed to make sure it wasn't freezing since we're getting a deep freeze this week. Maude is one of my newer flock members, around sixteen months old. I heard the tell-tale squawking that means someone is getting feather-pecked. Remember that toothpick holder where a wood pecker is on a swivel over the well of toothpicks and if you want a toothpick you push the bird's head down and it snatches a toothpick for you? That's what Maude was doing to the back of her sister.
I hollered "no!" real loud and sharp. She stopped. When she resumed, as I figured she would, I hollered again. She stopped! She did it a couple more times, and stopped each time I hollered. Then she wandered off to do something else.
As with Flo, this effect lasts for awhile. I don't know how long, but it is hopefully reprogramming something in the feather-picker's brain each time she gets hollered at when she engages in this behavior. In Flo's case, after several weeks of purely sporadic hollering associated with the picking behavior has apparently resulted in stopping the behavior. I can only assume it's stopped because her victim Joycie has all her neck and saddle feathers.
So, you don't need to be out in the run for hours at a time to perform this therapy. Just be alert to any bad behavior when you are out there with the flock, and holler at the top of your lungs, screw the neighbors, when you see it happening. Keep watch on the perpetrator, hollering each time she does it over the time you're in the run doing chores. See if your picker responds as mine have.
I'll be darned if this just might be the miracle cure!