If she is that far gone I personally would cull. If it looked like she would just need a little assistance for a period of time and would recover, then I would wait and see. Around here, I do not do extraordinary measures. I will care for animals that need some help and watch to see if it looks like they will be able to recover or not, but I am not the sort to do special setups for long term living. For instance, I don't do misters, ice bottles and things like that in the heat. I do make sure they have shade, cool water and make them mud holes so they can cool off in the afternoon, but my personal feeling is that this is the climate they live in and they need to adapt to it. Same with sick or injured birds, I don't do the vet for a chicken, if keeping it clean, keeping them calm and well fed and watered is enough, then I give them a fighting chance.
Running tally:
Cull: 1
Care: 0
She probably would never recover without some major splinting and physical therapy. Splinting may not be enough at this point.
I told bf I want to help this chick but I am not going as far as breaking it's legs so they can heal straight (as they would do for a human for a crooked jaw)
This chick, if left to live, would always need special care of some sort. It might have to be an inside chicken if it lived to adulthood. I would imagine it would still lay eggs in the end.
I would feel bad for it and be embarrassed when anyone visiting asks about why the chicken can't walk. :/