HandicappedPets.Net

This book https://www.amazon.com/Animal-Wisdom--L ... mal+wisdom has a story "Whose Birds Are These?" (p. 22) that describes how to wrap a baby bird in a diaper to correct "sprawl-legged" baby birds BEFORE the baby's bones harden.

In chickens, when they are splayed, I have successfully used a small bandage or piece of medical tape to "tie" both legs together, leaving about an inch of space in between. You also have to make sure that they are on a surface that allows them to have good traction.

An emergency brace is the best action you can take when you find your bird has a broken bone or broken leg, and then get it to the vet quickly.