What are the exact measurements of the coop and to how many birds? At a glance it seems fine and there appears to be enough going on to keep them busy, but if they are going to be cooped up in it for long stints in unfavorable weather, they might need more to keep them busy.
How exactly did you go about integrating the new-comers? Were they simply added, or did you follow a see but don't touch rule? With my established flock where space wasn't an issue, I had mixed results with adding new birds (hatched into the flock with see but don't touch till 2 weeks old) and found out one of my hens is prone to bullying. I've not had it result in injury, but she does go out of her way to make life tough on newbies.
You may need to do a bit of observation work to find out if there is a bird or two that are the culprits. With her being injured and chickens being curious things, she's likely to be attracting everyone's attention at the moment so it may not be the best time to figure out whodunit unless they start harassing someone else in her absence.
With mine, the harassee generally gives my pushy hen a wide berth - usually around a meter - and has plenty of room to move away from her without getting cornered. I've also been very strict with her to curb any 'antisocial' behavior, since we don't have a roo to break up the fighting. She now knows the sort of behavior I expect and stays in line.