Based on what I've read here (& I'm so grateful for that!), I think my chickens are showing signs of coryza. I have about 30 chickens, Siklies & Bantams, a year & a half old, never sick til now. I took in 14 new hens that were being given away, about 2 months ago. One of those has always looked a bit sluggish & "off," but no other symptoms. I noticed a sitting hen had a watery eye that kept getting stuck closed; I tried to clean it, but it'd come back. I didn't walk my yard for the few days right at Christmas, just shut up the two roost houses at dark. Big mistake, I think. Also, it finally rained for several days here, so chickens were out in it. I found a Silkie rooster alone, weak, with one eye swollen shut and terrible odor from goopy nostril/beak. Eye worm? No, the smell sounds like coryza, correct?? But the one rooster is the only one with smelly discharge. We went to our feed store the next day and got tetracycline powder for all the water, and a few amoxycillin pills which we quickly ran out of. The next morning, a perfectly fit young adult guinea couldn't get up, struggling with every breath, but clear eyes and no other symptoms. He died before evening! We continue to change water and put tetracycline in it daily. Back to the feed store and got VetRx and injectable Tylosin. We now have 2 Silkie hens with one eye shut, no energy, sluggish, one Silkie rooster with no symptoms other than sluggishness, and the original Silkie rooster that smelled horrible, now a bit better with no new discharge, but still weak and one eye still swollen shut. I rub VetRx on all the heads and put a drop in the mouth. Today, we started injection with the Tylosin. Feed store manager seems very knowledgable, but am I doing right to give half a 1cc syringe dosage of the Tylosin? I'm afraid I'm going to overdose & kill them while trying to help, but I can't stand by and see more get sick if there's something I can do to help stop more from getting sick. The rest of the flock is acting fine, but I watch them. They seem to do better with our warm weather for the past 2 days, but it's going to get cold next week. Our chickens are pets and losing the guinea was very hard. What more can I do to help stop the spread? I have to rely on whatever my feed store has for medicines. I realize y'all aren't vets, and I do not hold anyone else responsible for advice, but based on your experience, I think I can learn from people who have gone through this before. I don't plan on culling my chickens, even though I've read that they will be carriers for life if they live. Do you think the chickens 2 months ago brought in this disease? Why no illness til now? Whatever help can be sent my way, I am very grateful for your input. Thanks so much.