Leg problems in chicken - please advise!

Hello,
At my school, my friend and I are in charge of feeding the chickens belonging to the woman whose property we stay on. She has a lot of chickens and though she cares about them, there is very little hygiene and the place is rife with disease and all sorts of infections, especially scaly leg mite. Now a few weeks ago, we went into the feed room and found a chicken lying half dead on the floor. She had sores underneath her and the state of her legs was abysmal. There was some water and some feed with her, but I did not think she would survive. When I asked the owner about it, she said the chicken has "raven's foot" or something (I couldn't quite catch it). The next week, the bird was still there, looking miserable but slightly less dead. I patted her for a while and encouraged her to eat. Yesterday I found her again, two weeks after the initial time, all huddled in a corner. I drew her out into the open. When I first met her she could not walk, and staggered and flopped onto her left side. It was like her left leg was useless. Now she still couldn't really walk, but I got her to stand and stumble a few paces, until she stood up, shivering. The sores were gone, so I lifted her up to get a look at her. the poor bird is super thin. Her legs are covered in twisted growths, and in areas where it is sloughing off tight, pink, swollen flesh is showing. I didn't touch it because I didn't want to pick up anything I could potentially spread to my birds. Does this sound like a severe case of scaly leg mite? When I first met her she could not at all walk, and now she barely can. Is that normal for extended untreated cases? I know this bird is not mine, but I want to help her if I can. There's a chance I may have time to slip down to her this evening and rub some oil on her legs or something, and I'll see about buying some vaseline. As this is not my bird I cannot provide pictures. What does this sound like to you?
She is a lot stronger and perkier than when I first met her. When I left I had just shown her to the water and she was standing and drinking thirstily. She seems to want to hang on, so I want to help her. Any suggestions? Help is much appreciated.