Chicken having trouble standing/walking

[MarshaB]

We let our chickens free range every once in awhile and the last time one of the girls came in and the next day showed problems of standing and walking. She eats when she has the chance but the others are aggressive toward her so we have separated her. I checked for bumblefoot and don't see any spots. I'm not sure how to help her from this point. Any suggestions?

 

[nuthatched]

Age?
Diet?
Any chance she could have found anything toxic or moldy?