I bought my first chicks in May of this year, me and my boyfriend slaved away to build a large nice coop for them I don't want to think about how much money I put into it all. Once my hatchery chicks were old enough they went out into the yard and for 4 months they've lived happy healthy lives. I bought 2 silkies from a breeder and was planning to get a third but lost one to sour crop the other was killed by a hawk. I took it as a sign that I shouldn't raise silkies but it left me with an odd number of chickens and odd numbers tend to really bother me so when browsing through the flea market and seeing all those chickens in such terrible conditions I just had to save one (was my thinking) I purchased a skinny little dominique and kept her separated for 2 weeks (I didn't know they needed to be separated longer) I gave her worm meds and dusted her for mites and fed her bunches, when I thought she was healthy I introduced her to my flock of lively birds. 2 days later she was very sick, swollen eyes, snotty nose, lethargic. I quickly caged her but then that night I found another one just like her and for 4 days now I have found one or 2 sick chickens that i have placed in my sick bay in the garage. I cleaned out the coop sprayed stuff with bleach, I have been treating all sick chickens with Tylan 50 injectables since day one, I cloroxed the water sources, I replaced the pine bedding with sand, put antibiotic in all the water. But I am still finding sick chickens I now have 7 of 18 in the sick bay and they aren't showing much improvement. I am afraid it's Coryza but I called a poultry vet and he said it could be a multitude of things and that it's very possible it isn't something that will stick with them for life. So I am going to get a few tested for about 200 dollars which is pricey for me but I'm desperate to find out what this is, and if there is a chance I can save them then it's worth it right? I've been so depressed for the past few days, it hurts me to listen to them struggle to breath and cough and sneeze and try to look at me with their swollen eyes. I am worrying myself sick, trying to decide what to do. I feel like I'm going to lose them all, my boyfriend's father has butchered chickens all his life, he can cut their heads off very fast and in one swing, so I have asked him to kill them for me if I must put them down. I burst into tears now every time I think about it, I don't know what I'll do and I don't even know if I can stand getting more chickens after this. I love them very much but every time one gets sick it's another knot in my gut and I don't know how much more I can take. I don't want to lose my flock, so much love and hard work has went into them, but in the end my inexperience may have doomed them to a short life. Please someone I could use advice or some kind words, my heart can't keep breaking like this. I might be too sensitive for chickens.