Feather picking and Pinless Peepers

[kyuu]

Hello! I'm in a bit of a crisis and I'm getting desperate.
So one of my chickens has been pecking my other one (I only have two) and has given her a bald butt and is starting to peck her neck feathers and comb too. They have plenty of space (however, it's all just sand which they can dustbath in but not find bugs etc, any tips for me to improve their environment?), and I tried Blu Kote, Vicks Vaporub, giving them boiled eggs, scratch, which didn't stop the pecking, and now I have pinless peepers.
So I managed to fit the peepers on the offender, but now my other chicken pecks the old offender because she's got the peepers on. I already tried to put peepers on her too but she opened a groove on her beak from her nostrils so the peepers slide off. I tried scattering peepers around so she would get used to them, but she just won't stop pecking at my other chicken's face! Is there anything I can do to cure their boredom(suspected cause)/stop the pecking? The pecking's gotten worse since the wall in my backyard collapsed, so they haven't been able to free range. But they still can forage in a fairly small fenced grassy area which I think is better than their sandy coop (Is it?)

TL;DR I don't know how to stop my girl from pecking my other girl with the peepers!

Please help!!

 

[dawg53]

Hang a head of lettuce or cabbage in the pen. Purchase a used mirror at a flea market and put it in the pen.

 

[TwoCrows]

I had this same problem at first when I originally started using pinless peepers. For the first few days of having put them on the cranky hen, I had to give the birds something to do so they weren't obsessed with the peepers. I threw them flakes of hay, got them out to freerange, hung veggies in the run, put out seed blocks, lots of treats at first. Anything to draw the attention off the hen with the peepers. Unfortunately, the birds can learn bad habits and sometimes never forget. So do your best to occupy their hours for the first few days til the birds accept the fact that one of them wears peepers. Good luck!