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.