RIR are notorious for being something of a bully, especially in groups. When you put them together again, I'd do the 'Meet & Greet' thing (see the link to my chicken info site, below for how-to's) and act as 'mama' to defend the bantam.

Also, make sure that any bullied birds have a couple of places to hide--a couple of bushes work well. Just so they can get away from each other and out of sight.

Your bantam is no doubt distressed--she's going to be sore at first and unhappy. Keep her warm and quiet, and offer her some extra protein in the form of live mealworms or crickets, or scrambled eggs or cooked ground beef to help her heal and grow new feathers. Clean her wounds if needed and apply a bit of Neosporin to them (just a thin layer so she doesn't preen it all off) and watch the wounds to be sure they don't infect. Unflavored Pedialyte (get it at the grocery store in the baby aisle) for her to drink instead of water for the next day or so will help boost her electrolytes--a good thing for sick/injured/stressed birds. Keep her company and talk to her in a soothing manner.

The fact that she was pecked this hard was not a 'pecking order' thing--it was bullying, possible from stress and boredom/overcrowding. How big is your coop/run? Do they get access to fresh greens and allowed to free range? If not, consider tossing them interesting, time-consuming things to eat--heads of cabbage, raw corn on the cob--anything that diverts pecking from their flockmates and keeps them occupied.

More info on my chicken site, here:

http://jackshenhouse.com/

Enjoy your chickens!

Velvet ~:>