If she's flapping it well, and it's not hanging down too low, I would personally leave it. Just keep an eye on it, and consider adding steps to the perch.
Having an injured wing droop freely, and not immobilized very well could potentially worsen the injury, as the hen may try to fly up onto the perch, or get her drooping wing caught on something.
My first goal would be to assess her wing to determine the nature of the injury. Gently palpate each...