I have a 5 month old chicken which is going down very fast. I let my birds out every evening to roam the yard. They all seemed fine, then I noticed this hen was having problems walking. The longer I watched, the worse she got. Her feet are almost rolled up in a ball at times when she's trying to walk. I'm sure she will be dead by morning and was fine this morning. I say that because I've seen a few others go down that fast. So far I've lost 4 to whatever this may be. Does anyone have any idea what this is?