Limping Chicken

Hi,
One of my hens as developed a limp this afternoon. There is nothing obviously wrong otherwise, although she has done some runny poos in the recently, for which she is now taking antibiotics. She isn't very happy and just wants to lie still, although is still eating and drinking.
Any ideas anyone?

Echo what Bodger said.

Keep her warm and comfortable and see how she goes.

Pulled muscles can take ages to recover.  Watch for any other changes and give her some live yogurt to help her tummy after the antibiotics.