Here's the link for what mine is on, our vet recommended them, they're called Dasuquin. We've been giving her one a day, two if she played rough or we went hiking or something. We just recently upped her to two a day standard, as she's gotten older. I definitely do notice a diff fence if we give her 2 vs 1, she's much more spry. We highly recommend! Nutramax Dasuquin Soft Chews, Small/Medium Dog, 84 Count https://www.amazon.com/dp/B0030V9HV4/ref=cm_sw_r_cp_api_6iBUzb24EJ428
You may want to look into the DM genetic testing. Shepherds are most at risk for it. Since she is a mix it is unlikely but you never know. Also I have said it a ton today but only because it is really great stuff. You should check out Dasuquin http://www.amazon.com/Nutramax-Dasuquin-Soft-Chews-under/dp/B0030V9HV4/ref=sr_1_5?ie=UTF8&qid=1405225769&sr=8-5&keywords=dasuquin it has done wonders for many dogs.
I would really strongly suggest you try Dasuquin http://www.amazon.com/Nutramax-Dasuquin-Soft-Chews-under/dp/B0030V9HV4/ref=sr_1_5?ie=UTF8&qid=1405906440&sr=8-5&keywords=dasuquin Whatever the issue is, this will not fix it but I have heard really amazing stories of older dogs getting so much more happiness out of life after they started taking it. Bentley is taking it now and it very well might be the reason he is using his back legs more. Good luck with your pup!
Thanks for the tips! As for Dasuquin, is this the one you use? Did they have any issues when they initially started taking them?