I am going to suggest you splint her leg or use a body sling,reason is b/c she has the use of the rest of leg,just not the lower half,it could be an injury/dislocation. It is worth a try as she cannot go on like this. If it is painful,remove splint. Use a body sling(hanging t shirt cut with two holes for legs,make sure feet touch ground)in the event it is a slipped Achilles tendon, There is a way to put tendon back into place,but b/c you do not know what is wrong and it has been left too long,it will be very painful. She is probably in pain,but b/c your vet has her on meds(is she on Prednisone) and i do not know what they are,i am hesitant to suggest pain medication. You could try an epsom salt soak,this is great for sprains.sore muscles. I am curious as to why your vet did not take any x rays of leg just in case it is an injury. You could also give her vitamin b-complex supplements which help with inflamed nerves.
It could also be symptoms of Marek's Disease as previously posted.
The more i think about your girl,the more i am wondering if she may have a slipped achilles tendon in one or both legs. The reason i am thinking this is you mentioned she was found under a shed,this condition can happen with chicks as they kick/struggle to hatch,it is possible she was kicking trying to free herself. Try the sling method,do a search on slipped achilles tendon you may find other treatments for her.
She doesnt alway put her head all the way back. But she did that i think twice in the past 4 days. Shes had this for 4days. When we found her she wouldnt open her left eye. Her legs shake when they are cold. She is moving the left leg but not the right...
Before the vets, she was able to stand on her right leg and flap her wings. Now that we gave her the meds she wont move. She can move her wings up and down but doesnt flap them anymore. Not sure if its because she trusts me or what.she can drink and eat on her own if the bowl is in front of her.
Her poop is good and i dont see any change in it. Im making sure that she eats more than she drink but im also making sure she get enough water.
I thought about a sling to keep her suspended I guess ill try it.