3 of 4 of my 7 month old Wyandottes became lethargic Sat. morning and died. One was about a month younger and always was to herself and shy to the others so I didn't think she was that way because she was ill. There were no signs of respiratory problems, no poo issues, no bluing of the combs, not eye or beak problems, no injuries. They were fat and eating and drinking until that morning. I have 4 other different hens are in a separate coop that I've had for 2 years that are doing fine and the one Wyandotte that was still alive appears fine too. I have been keeping her in a cage in the garage for fear that she may be contagious. . They all shared the same pen area. Anyone have any ideas as to what happened?