This hen is several years old. Not sure how old as she has been passed around. She seemed fine until this morning. She is just standing in one spot, closing her eyes. She is drinking water. Saw one watery yellow poo. Eyes are clear. No nasal drainage. Her comb is floppy but red. When walking, she seems to stumble a little bit. Just separated her from the others. Everyone else seems fine. Her breathing seems a little labored but closed mouth. Suggestions?