Had the strangest thing happen. Night before last when putting the hens to bed, one of the girls was "sneezing" a wee bit. It was late and myself not feeling well from a cold, locked them in tight for the night. Yesterday when I got home from work, I let the girls out of their run and sneezy was still sneezing but acting normal in every other way. I picked her up to have a look and she indicated that she was not happy about that, which is not uncommon. I put her down and quite suddenly she was "sneezing" out of control, started flopping around, sort of convulsing and in a matter of half a minute or so, was dead. Does anyone know what caused this?