About four days ago I started noticing our adult cochin hen was not walking around very much during the day. I picked her up from the spot she had been hanging out in and set her next to the food and water. She started eating and drinking like crazy as though she had not been able to make it over to the bowls all day. After that I set her down and watched her attempt to walk when I realized that she is tripping over her left foot, and falling on her face. When I examined her legs, I saw that her left leg was kind of just hanging there. No bumblefoot, no injury. and she did not react in pain when I touched it. I thought maybe she sat on it too long and it fell asleep, so I massaged it a bit, but no luck. She continues to move around only occasionally during the day, and continues to trip. I trimmed her nails but that did nothing. The color in her skin is good, her eyes and beak look clean and healthy, she does not fight with the other hens, no sickness or parasites with the others going on right now, and she is enclosed and protected from predators. She is actually the only one laying eggs right now as well, and she eats and drinks as well as the others. Seems healthy overall but her mobility is badly limited by this. I can feel warmth and some muscle movement in the leg when I examine it, but when she tries to walk it just gives out. Any thoughts?