OK, so I'm new to chickens however I spent ALOT of time prior to getting chickens on researching what I needed to do, how to best care for them, etc. Two weeks ago I bought 12 chickens from one chicken farmer. Having never bought chickens I didn't know what criteria to have and quite honestly I never came across any information while researching. They have a 4x10' coop with a 8x10' roaming area. After having them about one week I noticed one of my chickens with a closed eye that soon turned into a small amount of drainage and she was "gaping." Another chicken began having a significant amount of smelling greyish drainage from it's nose and crusty eyes, but no "gaping." We took these two to the vet and were given medicine for gapeworm. We quarantined both of them and another that we noted with closed eyes (we got medicine for her too). Well all three of them died today. And one of the remaining 9 looks like she has bubbles in the corner of one eye. I'm thinking either Coryza or CRD. So what do I do? I'm planning on treating the others as soon as I can get Tylan from the feed store tomorrow but can I expect them all to get it and die? And if they do where do I even begin to look for new chickens? It seems that this is a controversial subject. What immunizations do I need to ask about and what type of hatchery do I need to find? BTW these are laying pullets but I'm thinking if there is a next time I need to just start with babies.