Watery poo can be from drinking more water...diet.change or other issues. Just keep an eye on it and make sure it doesn't get worse. As for the sling...try it for a few hours at a time. This will be less stressful for her.
Bless you for taking th in......Like stated above...she sounds like a meat chicken..which are bred to put on huge amounts of weight before slaughter. This puts huge amounts of stress on their legs and bones. the bear areas sound like pressure areas from her sitting for so long. I'm not sure her...