For the past 3 months I've been fighting with something in my chickens. They were sneezing, coughing and wheezing. I'm semi-new to the chicken thing, having them for not even 18 months, but until March of this year I had only 6 and now I have 3 pens and 25 total (plus 7 meat birds). * First I gave them Duramycin-10 for 14 days. I thought they all got better, but one month later they started to show the same symptoms. * I gave them Duramycin again, majority got better, but a few weeks later, same thing with 60% of them. * It then came to me that they probably had cocci, so I gave them: ** Corid for 5 days, ** De-wormer for 1 day, ** Rooster Booster for 5 days ** I also powdered them with lice/mites dust powder on the day before I started the Corid treatment. I did that for 2 days. Now I have the young birds (3 months old) looking "sleepy" and sneezing, even saw mucus in the mouth of one of them. I also have a couple of 5 months old sneezing with the heavy mucus sound. The young ones are not active, kinda droopy. And I have one adult that isn't too happy, but I'm treating her for a mild case of scaly legs. My runs are muddy now but this will be fixed this week, since the rain finally stopped and they will get dry - and I can add 2" or 3" of sand in them. Coops are cleaned once/week. What else can I do?? What could it be??? I'm lost... Thanks in advance!