Yesterday afternoon my son came in and said that one of the chickens wasn't walking right. He brought her in and I examined her and her left leg did look a little off (limp) but she could move it so I didn't think much of it. Then later when he brought her back in that night, when we were locking them in for the night. He set her on the ground so I could see and he said he found her lying on her back in the coop. I checked her over again and she couldn't stand on her leg. then she fell over almost on her back right in front of me. I tried to pull out her wings to check them and the right one was fine but the left wouldn't move. It was stiff. We gave her some food and water and put her back in the coop for the night (that is were the warming light it). This morning he brought her in and said he found her on her back again. so we put her in a box in the living room with come food and water. She is eating and drinking and looking at us, watching us walk around. She is a Coochoo Maran and only about 15 weeks old. What is wrong with her? What can I do for her?