We have Barred Rocks that were born in Feb of this year. Great layers so far. Last weekend I noticed one of the females looked a little Ruffled. I watched her for a bit that day and she seemed maybe tired, or just didn't look right to me. I watched her eat the scratch that we give them everyday along with day old bread. She ate and drank normally. Yesterday, my husband was feeding before I arrived home from work and he found her dead on the floor of the coop. I have racked my brain to figure out why she just up and died all of a sudden. This is the first one we've lost since they were babies. Well, then today I remembered that the weekend before last, we let them out to free range for the first time while we watched them. They did enjoy that alot. I also forgot that we had put moth balls down in a couple of places on the outside of the pen where another animal had been digging. Now, my question is, Did the moth ball kill her if she ate it? Yes, I'm sure it did. But, could there be anything else that we need to watch for with the rest of the flock, just in case it wasn't the moth ball? These chickens were vaccinated at birth and we keep everything clean in and around their pen. Could they still get diseases? Thanks for any input from anyone.