The dog is a little hunchbacked. If it is not caused by parasites, you can check to see if the dog has a stomachache.
If your dog is always hunched over (not particularly obvious, but visible), his body curls up into a ball when sleeping.
Use your thumb and other four fingers to separate, and pinch the dog's belly with a little force (don't be too hard, just a little force) from both sides of the dog's body. If the dog resists, If you lift it up, you may even tremble. Then it might be stomachache.
In this case, it will generally not cause the dog to hunch all the time, and it will be fine as long as the pain is gone.
It may also be caused by calcium deficiency, arthritis, etc. You can go to E Pet to find some Weishi calcium tablets to feed and check the situation.