I had to separate 2 hens once because the were just mean. Being New Hampshire reds they wanted assert their authority young but slowly getting better. I heard separating the bullies for a week or so starts pecking order over but I don’t know... mine were young but in this situation the issue would return due to space. Even keeping them for eggs they need the proper space to be healthy to lay. Pecking can get worse causing severe injury over time. Measure the coop sf and then the run sf. That will help determine the amount that will be happy and healthy in the areaMy goodness they’ve put you in a tough situation. You sure are a thoughtful babysitter too. The Barred Rocks don’t have a spot on them.
The pinless peepers on the Barred Rocks will immediately solve the problem. However without former practice you’ll need help putting them on and then especially make sure the Barred Rocks are eating and drinking with them on. They need bowls for that, not regular bird feeders.
The flock block is a good idea too..,it’ll take those BRs a few days to chow through that but they’ll be busy all day or so full they won’t have time to peck feathers.
Something I was thinking was borrow a tall dog X pen or get some tall chicken wire and separate the Barred Rocks from the others in the closed pen they are in. Gotta be secure and safe though, and have food and water on both sides, chickens are masters at getting in dumb accidents.
Or take two big wire dog crates if you have access to them and separate those BRs from the rest in the pen. Put the crates in the secured pens, away from the sides in case that fox wants to try anything.
Does this whole experience make you want to get chickens? Hahaha...