Went in hen house first thing this morning, all OK. Opened sixlets cage and hen house door then went to get feed and water. Heard one squeal. Went back out and found rooster in hen house doorway and sixlets in open cage with 1 dead. Think rooster was the problem. Now I have hours of reading to do about separating and integrating chickens of different ages.....looked closely at pullet. Unable to determine cause of death. Totally sucks!! This is 1 of 6 if last chicks I incubated and hatched. It is almost 2 months old.