That's not good! Yes, a vet is a very good idea. It sounds like it might be a compound fracture? Are you sure it hatched that way and wasn't injured after hatching? I'm surprised it could even hatch like that; they need their legs to be able to turn in the egg to zip.
Chicks like the one that you hatched are usually suffering from a poor diet on their parents part. That or else there is something amiss with the parents' DNA. You are likely looking at 100s of dollars in vet bills with only a slight chance of a satisfactory outcome.