It would probably be a good idea to get her checked by a vet so that you know whether it is likely to be a temporary or permanent problem. You will then be able to make an informed decision regarding the best course of action. I'm assuming you know that her legs aren't actually broken. Are they completely paralysed? Can she move her feet? Can she stand at all if you stand her up? Could she have hurt her back in any way?
If she were mine I would take her to a 'chicken friendly' vet to be checked over and if it was likely to only be temporary then you could decide between yourself and the vet a time limit to give her to see if she improves. Of course he may not be able to tell you what the problem is and it may just be a wait and see situation, but at least if you see a vet you know you've done all you can to help.
In life not everyone follows the same road. Especially if their Sat Nav is broken!