Sorry about her blood work. She may have ascites (water belly) from the liver problems. That is very common in older hens, and goes along with reproductive disorders and also cancer. Ascites can cause labored breathing. Reproductive problems can cause problems walking. I tend to let my hens live...
Yes she has scaly leg mites. That needs to be treated by massaging oil into her scales to smother the mites at least once or twice weekly. It sounds more like she has sprained her leg or hip. I agree that forcing her to rest the leg for a week, and stopping her from roosting would be helpful...