My wife established a small two hen flock this summer. A Buff Orffington and an Americana. About 3 weeks ago the Americana started to have raspy breathing, a day later she was moaning considerable discomfort - we brought her inside for one night, It was cool and damp but not below freezing, their coop is dry though their run was damp. We treated with antiobiotics and brought a heat lamp into the coop at night. She seemed to improve for a while - raspy breathing was much better, I never noticed any discharge or crusts. Comb color was good and pink. The eyes were clear. She would perch on the roost without a problem. There was a possibility of some moldy food - and also we fed them popcorn just before the hen first showed symptoms. Anyway this weekend she got worse, sneezing, coughing, crying/crowing throughout the night. She still was eating, drinking and running around. At about 10 Monday morning I was alerted to trouble by the healthy hen's loud and insistent alarm. The Americana was dead and still warm to the touch. Crop felt normal - maybe very little in it. No sign of discharge or fluid anywhere. Her feathers were in good shape. We buried her 3 feet deep under the orange tree and scattered rose petals on the grave. Could this be a non-infectious disease like a heart problem? If it was infectious, I am sure the other bird would have gotten sick too. Not sure if we want to replace her or get out of the chicken raising business. Our Buff is very lonely now, she keeps calling and looking for her coop mate.