Hello! While new to this forum (actually, any forum for that matter) we have raised chickens for about 8 years; small flock of 12-20 mixed breed birds for eggs and enjoyment. We have a 2.5 year old Silver Laced Wyandotte with respiratory problems (a cold). I have spent a few hours scouring the internet and have come back with three or four frequency recommendations for Tylan 200 injections for respiratory problem and thought maybe I should join a forum and ask some fellow poultry people their experience. I am (fairly) confident through my chicken health book and the internet that the correct dosage for this sick bird is .5 cc. As far as schedule/frequency, I have seen online (each repeatedly): - 1 injection followed by a follow-up injection 48 hours later - 1 injection am and another injection pm for 3 days not more than 5 days - 1 injection am and another injection pm for 7 days not more than 14 days They are SO different I'm not even comfortable taking an average The sick Wyandotte had some respiratory issues a few months ago (winter) and we gave her 1 injection followed by another 48 hours later at that time. She improved to almost better, but never seemed to 100% completely beat this thing. Whether its the stress of summertime heat/humidity or just reoccurance, she's getting worse again. We gave her an injection 2 days ago and she seems to be 'stable' once again. I have heard that chickens can build an immunity to antibiotics just like people. Lastly at that same time in winter when the wyandotte was sick we had two others with colds; 1 injection followed by another 48 hours later did the trick for them. SO, I sure would appreciate any recommendations you might have for me. I was planning on giving her another shot tonight and seeing where it goes; but I'm wondering if some of you out there feel that after it not doing the trick for this chicken in the winter if I should try one of the other longer treatment options? and LASTLY we purchased the Tylan 200 a few months ago (Dec 2010) and it has been capped in the refridgerator since. Still ok? Thank you!