Please advise. On thanksgiving 5 of my 6 hens were killed. I went and bought two new hens to place with my survivor. A few days after getting them I noticed one of the new ones was sneezing with a bit of clear discharge from her beak. After watching her to see if she presented any other symptoms, she did not. However after a couple of weeks my surviving hen started sneezing with some clear discharge. I started them on tetracycline. I live in Colorado and we've had extreme temp differences from day to day and after almost three weeks my hens are not any worse but don't seem to be much better. They do not present any other symptoms and I am at a loss for what of what is wrong.