A few days ago one of our rhode island reds was acting sick and lethargic so we brought her inside for care. She was very lethargic, stumbling when walking, difficulty breathing and making a rattling sound when breathing. She wasn't drinking much water, but eating a lot. She eventually died, today, after about 4 days. Now one of my wyandottes is beginning to stumble when she walks- she is still alert, eating and drinking, but has difficulty walking (kind of limping and floppy) and sits down a lot, and has diarrhea. We just separated her from the flock and brought her inside. I did some research and a lot came up about Marek's disease. However we have had these chickens for at least 2-3 years, and they've never had problems before, until now. It is also coming on just after an unusually big rain, which left their pen muddy and wet. Could it be something related to that?? Any help is appreciated!! Also any ideas on treatment.... thanks!