I went out to the coop yesterday, and my 3 1/2 year old hen was laying by the water dish w/ her head tucked down and eyes closed. She was dead- the day before noticed no problems whatsoever. She looks perfectly fine. Any ideas on why she might have died? She had been laying fine as well- about 4 per week from her. Please help! My other 11 hens look and act fine as well.