One of my females does not look good. She's sitting very still with her head hanging down, her beak touching the ground and her head twitching occasionally. She doesn't hardly move but if she gets scared she will flail around, run into walls and then flop down. I separated her and gave her water. I didn't check them yesterday (long work day) but she was fine Monday night. She is missing a few neck feathers but it just warmed up here and the boys are frisky. I don't see or feel anything else wrong with her. Any ideas?