We found one of our birds dead this morning. We have no idea what happened. I wasn't really out with them yesterday as I've been sick for the last few days. She went into the coop herself last night and my husband said she didn't look injured. I have no clue where to start to figure out what happened. He said that she looked to have died in her sleep. My cockerel hasn't crowed all morning. Is this normal when he looses a pullet? Should I be concerned about my other birds? The eggs? What do I do next?