They can become obsessed with wounds and blood. So if you have to keep picked on birds separately for a while until they heal, do it. They can kill each other over wounds, become cannibals. Just keep everybody in sight of each other so mixing them back together isn't an issue.Thank you all for the warm welcome and advice!
I was going to wait another day or so to watch this little one and let the wound heal up a bit so I could move them all at once, but I walked out to the garage where the pen was when I heard some squawking and they had started picking on another one to the point of bleeding feathers. No open wound and only about 3 feathers were broken, but this did indeed make me move them out to the coop, as was suggested. Temps might fall a little bit tonight but I'm giving them a heat lamp just in case they need it, and I'm going to keep an eye on them through the evening. They seem to immediately love the space that the coop provides though, so hoping for happy chicks with no further incidents for the time being!
Thank you all again! I'm glad I found this place, I wouldn't have known how to handle this situation otherwise!