One of my hens, a broody with month old chicks who lives in a separate little run of her own fell ill suddenly. Yesterday she was perfectly fine. Today around noon I found her sitting on the rim of the water bowl in the run fluffed up, with her eyes closed and breathing very heavily. I noticed that her head and face were swollen almost like a balloon. She didn't react to anything. I left her alone because she looked as if she was about to die any moment and because my first thought was, yikes! Avian flu! I looked several times during the day and now in the evening she was still sitting there, looking worse, her neck also swollen and her face discolored dark brown, still breathing slowly. Her head is hanging down and she doesn't seem able to lift it up and doesn't react at all to calling, offering food or to being touched. The month old chicks are fine, so far. Oh, and I noticed that there was an egg in the sleeping box - her first egg since she hatched the chicks. No idea if that is connected somehow. And - last week another one of my hens died suddenly for unknown reasons. But she was in a different coop/run. What's going on? It's not the season for Avian flu. What disease could this be and what should I do about it?