Hey, I have a foster dog, he is about 6 years old, and is a doberman/GSD mix. I was wondering if there's anything I shouldn't be doing with him , for example something that might strain his joints or something. Is it okay if he jumps over things? What about teaching him to stand on his hind legs? I don't really know much about the subject of hip dysplasia or anything, so bear with me! Haha.