I noticed several of my chickens are getting watery eyes that have bubbles in them sometimes and the lids seem to "droop" funny. They seem to be fine one minute and the next their eyes look like this and just a few days later I find them dead. I thought it may be a funny strain of the respiratory illness that causes their sinuses/eyes to swell but I'm not sure. It seems the ones that have swelling seem to last a lot longer than the ones whose eyes get bubbly/watery but the swelled up ones look worse. Any ideas? I was giving them Tylan 50 but it doesn't seem to be working. I had around 20 chickens around 2 months old and I'm down to just 2 from that group. I've got a bunch of chicks that are still in the brooder right now but I really don't want them to mingle with the others if this is serious. I don't want any disease in my flock. Main question: Is this something that my birds will carry forever if they get it and will they transfer it to the rest of my birds even if they get over it and aren't showing any symptoms or will they only transfer it when they're sick?