Hi there, I came home today to find my 6 or 7 year old Black Star hen laying on her side, not willing to move. If another hen steps on her she will move, but wobbles a little. She hasn't seemed interested in food much, but I have given her a little bowl with electrolyte water and she ferociously drinks it. It is quite cold in Wisconsin being about 0°F today and about 20°F inside the coop. So, I would assume that mold or many bacteria can't survive in there. I've also heard about Marek's disease, but from what I've heard it commonly only occurs in chicks. Also, her eyes appear normal and are not that cloudy blue color. She is really a sweet, lovable hen and the only remaining of my original flock. So, what do you think this could be. Is she just getting old? Is she calcium deficit?