I have 29 chicks (had 30, but a small one died at 4-5 days old). They are Rhode Island Reds and Shaver Reds. They're all doing great. Fluttering, perching on me, gobbling feed and even starting to catch a worm or two when they're outside for short periods on nice sunny days. Just now I went to feed them, and found one of the Rhode Island Red chicks dead by the water dish. I found no scratches or marks on it. There's no diarrhea. It was one of the larger ones too. They still have the heat lamp (which I turn off of hot days or it gets too hot.) They have plenty of feed and water available. They'll be 4 weeks old tomorrow. Any ideas as to what could have gone wrong? HELP!?