So it's not just this one chicken with a swollen eye, you're also having others with respiratory problems? That sounds like a respiratory disease. Have you recently brought in new birds?
Edit: Actually, I just took a peek at your post history, and it looks like you've already had problems with a respiratory disease, so yes, this is a respiratory disease. Your birds are going to keep getting sick from it.
It could be any number of respiratory diseases. Some of them can be treated with antibiotics, some are viruses and can't. Most of them the birds always carry after they contract it. So you need to either close you flock, which means you never sell or give away any birds, and keep medicine on hand for when they have symptom flare-ups, which they will every time they're stressed, or you need to cull the entire flock, wait a while for the disease to die off in the environment, and then you could start over with new birds that weren't infected.
You may also want to get your birds tested to see which disease it is. There's a lab called Zoologix that can run a panel for you to find out. It costs $98.
If you want to go the treatment route, then I would start by trying Tylan 50, since it works on a couple of the diseases. It's only sold in the US labeled as needing to be injected, but you can give it orally. It looks like someone already gave you the dosing instructions last time you posted about one of your birds being sick with whichever disease they have. Did you try the Tylan? Did it alleviate the symptoms?