I've known several people who have successfully splinted a chick with splayed legs. The chicks grew up and walked a little gimpy but held their own with the flock.
I myself haven't had a chick with splayed legs (yet).
I have two gimps and they hang out together. Both are BLRW, one a Roo the other a hen. They seem to know that each other is not quite right. One has persistent pasty butt, the other has a crooked beak. Tried everything for the pasty butt and she regularily has to be washed. The one with a crooked beak is holding his weight on.
People tell me to chop their heads off but they aren't hurting anything. So until their disabilities hinder their quality of life, I'm going to leave them alone.