You've done all there is to do, I'd say. Repeat the ointment for a few days if it continues -- but mostly, don't touch the eyeball itself, or handle the skin in the area if possible. Just put a little ointment on the lower lid. It will spread across they eye. Hopefuly, time will be all it really needs.
You may be abe to put him back with his flock in a day or two -- he will be happier with others. Or choose one and put it with him, for company. Just supervise for a bit to make sure they dont bother him.
They peck to explore their world, of course, and sometimes peck one anothers' eyes. Things like a larger brooder with mre to do will help this. Add items to jump up on, hide under, etc., and mvoe them around. Bring thema clump of sod; they will love it. Take them for short outings outdoors if you can - you'll need a temporary fence, maybe an old playpen or something of the sort. And try making the brooder a little cooler as well.
Good luck!
