I have had 4 hens for the past 3 years and no problems. This past spring I got 8 more as chicks. I kept them separated. 5 out of the 8 ended up being roosters so I returned 4 and got 4 hens in their place. I moved the ones from this spring in with the older ones. A few weeks later one of the original spring chicks literally died suddenly. Never lost weight, never acted odd, nothing until about an hour before she passed. Since then another one of the original spring chicks have died and 1 of the new hens. I live just outside of raleigh, NC and want to know where I can have the remaining ones checked or where to test one that has died if I preserve it? I obviously don't want to lose anymore of them.