So I am new to keeping chickens, and I have 6 currently. 4 laying pullets that JUST started, one 4 month old pullet, and a rooster. Last week I noticed one of them having a raspy sound to her breathing, but I thought it was because she was trying to eat caulk (different story, rinsed out her mouth and she was fine), but today I noticed all of them sounding congested and opening their mouths to breathe. I live in Kentucky where it's cold now, in the 20s, but their coop is well ventilated. Nobody is acting all that odd, in fact the laying hens are all out and about even in the snow. The other two are in the coop, but that's pretty standard for them. They are laying normal eggs ( some have calcium deposits but they are brand new layers). No other symptoms noted. So my question is, given the time frame here (it's been a while since I first noticed symptoms) and given that they don't seem too bothered at the time, should I dose them with duramyacin or tylan 50? I'm leaning towards the duramyacin both because of the cost and because of the fact that I don't know how I'm going to inject 6 chickens with medication for 5 days, but if its possibly a life or death matter I will do it. This is the first time I've ever dealt with this so I don't really have a gauge for how serious it is. The newest member of the flock was the rooster, but that was 2 months ago and he did not seem sick when I got him. Is this just a winter thing that I should dose with duramyacin? Or is this a more threatening thing that I should dose with Tylan 50? Also, I know you're supposed to stop eating eggs with duramyacin, is the same true with Tylan 50? How does anyone feel about VetRx Poultry Remedy? Thanks for any input I am desperate for some guidance because now I'm paranoid I have waited too long.