Hen- one leg won't work, covered in mites

So I'm relatively new to this chicken keeping stuff and I'm beside myself trying to save one of our hens, Maude. It started on on Thursday of last week. We noticed when all of the other hens were roaming around the yard that Maude was just laying in the sun. She's very skittish and normally takes off anytime we get too close but when we approached, she just laid there. We picked her up and put her up right and she took a couple of wobbly steps and laid back down. We picked her up a second time and she walked back into the coup where we shut everyone up for the afternoon. Friday morning when we came out she was on her side in the run and the 6 other hens were pecking at her. So we brought her inside and set her up in the bathtub with pine shavings and food. At this point she was walking like she was drunk and wouldn't take more then a handful of steps at a time. She had poop all in her feathers so we cleaned her up and noticed she had a lot of mites and/or lice on her. So we went to the local feed store and got diatomaceous earth and covered her in it. She was able to push down with both of her legs but one of "feet" just doesn't seem to do what she needs it to do. Saturday was pretty much no change from the day before. Sunday morning when we checked on her she had one eye closed and we couldn't get her to eat or drink much. We put antibiotics in her food and water but I don't think she got much becuase of how little she was eating. By Monday both of her eyes were closed and she wouldn't eat at all. Honestly we've kind of just been waiting for her to die but she just keeps holding on. Finally last night I went back to the feed store to get something stronger for the mites/lice because it didn't look like the diatomaceous earth has gotten rid of them. They suggested that I wipe her eyes down with the antibiotics as well and sure enough she opened her eyes right up. When we wiped them, there were lice/mites all over the tissue. So we are basically back to square one at this point because she's eating and drinking but her leg still doesn't work. Sorry for the long post, I just wanted to include all of the details.