Maybe call the vet and ask? Poor girl...thank you for wanting to help her live life to the fullest:)
Hi Elizabeth !
Crackling noise can be lots of thing! First off she could have a minor fracture in one of her bone that makes the crackling sound. She could also have twisted one of her muscle / tendon and this could also make sound. If she had a minor fracture it could of healed and now it could be the crackling sound from the '' fix '' bone and it could be arthritis. I would make a quick stop to the vet to do a exam on her bones / muscles just to make sure.
Best of Luck
Karyne , AHT and Sheldon