Comb pecking

A few days ago I noticed one hen - with the largest comb - getting black marks. I thought it was frostbite, but several posters here rightly guessed it was something else - pecking. Today I finally witnessed the behavior myself, as several hens would approach her, stare at her comb, then grab it. She seems to have some learned helplessness going on as well, since even though we were out in the yard, she squatted down to the ground, closed her eyes, and took it.

I'm sure some of this comes from them being more confined lately. We lost a hen in broad daylight a few weeks ago, and have been keeping them cooped since while we order and install an electric poultry net. But now that it's happening I'm not sure what the best course of action is.

Does she need to be separated for a while? I've read some suggestions of pine tar, blue kote, etc, but will that suffice? I definitely have room to take her away to the garage, or would a pen inside the coop be a better idea? I'd hate to keep her separate for too long and then the hens treat her as a stranger.

I would separate her to allow the comb to heal. This way the hens get out of the habit and the black spots will fade so they are not tempting to peck at.

Depending on the size of you coop it may be best to keep her in a cage within the coop so they can see her but no peck at her. If you do not have the room moving her to the garage is a good option.

I would try blue mote first, it sounds like she's a bottom hen and separating her could cause her more problems, and the others are taking their frustrations out on her, make sure you have places for her to go to get away, things to go under or in or on top of, hopefully you can get them back out, you could try adding things like cabbage or flock blocks or grass clippings or falling leaves, hay, stuff for them to occupy their time.