Got a head-scratcher here and I'm not sure how to proceed... 2-3 weeks back one of my chickens was sneezing, sounding kind of like a human with a bad head cold (sounds wet/mucous-y, for lack of a better way to describe it). I isolated her for about a week to observe, gave her yogurt and her normal feed and water. No change, so started dosing her on Tylan 50 (once a day, 1/2 cc). It's been a week on the Tylan and she seems to be cough-sneezing less, but it's still there. Actually, it only really manifests when she is stressed, like if I pick her up to medicate her she's not happy about this and wiggles and then the snorting starts... Outside of that she eats normally, pretty much the same greedy-for-snacks hen as always, and her comb is still bright red and I don't think she's lost any weight, not much difference I can feel when I pick her up. I haven't noticed any weird discharges or swelling/dripping/oozing anything, but it concerns me that she's still making these noises. While I want to put her back in with her flock mates (she'd very clearly like to be back with them), I don't want to put her back in if it means she's going to pass this mystery sneeze onto the rest of them...what do I do??