some people take their chickens to the vet. it is not practical for most but it is something you could consider. it is her best chance to live with a working leg and without pain. i do it. it is expensive but they are my pets and i am happier taking them to the vet and paying the bill than the alternatives - just my personal choice. i hope it heals well and she regains full use of her leg. if it doesn't, she can get by with one leg but she might get picked on.
I have had a 3 legged Cochin for 6 years. i got her at 4 months, she was injured as a chick. the farmer was going to cull her. She was big relative to the rest and did well for the first 4 years, did not get picked on and got around great. she is "Special Edna"
. I then added young ones to my flock. the young ones will kill her if i leave them together so she is separated with a few docile smaller hens.
if you do go to a vet, for this particular problem you'd want a very good avian vet, one with chicken experience. otherwise i might not bother unless you just need antibiotics or simple pain killers. i could be wrong...just my experience that the less experienced avian vets will inevitably do their diagnostics and in the end send you home with pain meds, antibiotics and maybe inject some fluids, all of which i can do on my own. however i am clueless with a possible bone injury like this. if you are by chance anywhere near northern CA I highly recommend Dr. Speer in Oakley CA. He is a world renowned avian vet and actually cheaper than avian vets that are closer to me.
if not i think you are doing all you can, i'd try the splint as another suggested. you could also ask for advice on BYC for a pain reliever - I've never given any to young chicks but have given aspirin, meloxicam, carprofen, butorphanol and metacam to adults. I think metacam and meloxicam may be the same thing, not sure. Butorphanol is pretty heavy duty (i think an opiate) but the others are more of an anti-inflammatory.
good luck!