This is something pretty small, but I've noticed that when my bird sleeps (they duck their head), the halo stays where it was before, so it just looks like a weird oval on their head. Soo my suggestion would be for the halo to move down with the bird when they sleep.
This is mainly for birds to look better when sleeping when equipped with a halo. Not sure if such a small thing would be worth the time and effort, but y'know.
CrystalPistol/NP sold galaxy for 3k