My barred rock, 6 months old, since last night is just sitting there, won't walk. I looked her over this morning and she has no injuries, no hard tummy, looks great. When I set her down she pulls her legs up under her tummy - she doesn't extend her feet towards the ground. When she tries to walk, her feet curl up and she has to outstretch her wings to keep from toppling over. She's otherwise acting normally, clucking/talking to me as I looked her over. She's one of 30 who free range, all others seems fine. I don't know if she's eating/drinking as I got home late last night and my bf just told me this morning about the problem so I checked her real quick as I left for work. Any ideas?