My chicken is hurt
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Is it possible she could have gotten it caught in the fence? It sounds like an acute injury like a sprain or break. Have you felt her foot to try and feel the bones? If you help her and position her foot will she bear weight at all?
I have heard of people making makeshift splints or securing their leg to them with vetwrap so it can heal (sort of like a cast or brace). Check her out really good and make sure now that the others aren't picking on her and that she has easy access to food and water. Sometimes the sick or injured ones get pushed out of the feed and waterers and are picked at.
Keep us posted, she's a beautiful little girl.