If it were me, I would give it a day or two. As long as there are no respiratory symptoms involved, it may very well be just hurt and will heal or not on it's own. Just keep a good eye on it, if you start seeing any other type of symptoms, please post back. Right now, I'm really not sure there is anything you could really do to help. There are threads on BYC that tell how they have used triple antibiotic ointment and other ophthalmic creams, but myself, I really try to stay away from that. A coop is a dirty place, no matter how clean we keep it. There is dust and all kinds of other not so nice things floating in the air. You put an ointment on the eye and that stuff floating is going to end up sticking in it. If your hen is healthy to begin with, chances are you will not have to do anything at all. Right now, even though it looks very clean, the nost i would do is get a bottle of saline eye drops, keep this chilled and wet a soft piece of guaze with it and wipe the eye a couple of times a day. The saline drops have a slight antibiotic property and the coolness will help with any swelling.