Leg injury or vitamin deficiency

[mj0]

How do you tell the difference? I have a 6 month old brahma hen who lays with her one leg back behind her. I just got her up on a sling last night she had access to food and water at all times, have been giving her 3cc of poultry cell a day. It's been about a week. Just wondering if I need to be more aggressive on vitamins or continue with what I am doing . Pic is her current set up in a heated building

 

[MysteryChicken]

Sounds like Marek's Disease, based on the description of how her leg goes behind her.
That's classic with the Disease.