Check with Zoom Dog supplements in Golden, CO. My dogs were on them for years and hunted/lived forever with visible discomfort only in their last years - after retiring. I know the owner of the company and the supplements are developed with the chief of canine nutrition at Colorado Stat University's veterinary school. The company sponsors some trial dogs - retriever and pointing dogs, and they give back to the industry. If you call them for info, you may talk to Neal, the owner (and a bird dog guy himself). If you do, tell him I said hello.
