Tony, you can also give them the glucosamine/chondroiten tablets that they sell for humans... that's what my vet recommended I use for Tweety.
Several of us have also switched to the Victor 26/18, purple bag, as the 24/20 seems to have changed. Dogs are doing real good on it.
Big E thought there might be a difference in 24/20 as of late.. The dogs don't respond as well to it
Thanks for all the comments everyone