Pine tar sounds like adding insult to injury for the poor girls who have been picked. We used a red light bulb, and blue cote when they were still young. Most recently we separated the wounded hen, and I also grabbed the bad hen and got an emery board and filed off the sharp edges of her beak. She can still eat, but she can not grab and hold the feathers long enough to pull them out. I think they get grumpy this time of year. It must be the gloomy days. Nothing better to do so they pluck a chicken. The only time I have had feather pulling issues is when we have dreary rainy overcast days that last and last... and last...
Come to think about it, I'm ready to pluck something too!