Not good! Are your chickens perhaps bored? I would separate him, or at least get some blue kote on him right away and watch that they don't go after him further. Watch the flock carefully to see what is really going on--are they pulling feathers? Are they eating feathers? Is more than one hen doing this? Is he being too docile and allowing them to pick on him? If so, he probably needs a break away from them--at least until he heals and they can get out of the coop more.