Hen falling to side when she walks- HELP!

[fourleaffarm]

We have a 4 month old cochin, she was perfectly healthy until yesterday. When she walks she falls onto her right side, kind of just flops over- like she can't hold herself up. Any idea what this may be and how to treat it? She is eating and drinking, I added some vitamins to her water, seemed to help a little bit.

I really have no idea what this could be, any help/ideas would be greatly appreciated!

 

[chicken crazed 1o1]

Maybe her leg is broken

.