I'd like to start Zak our retired racing greyhound on a joint supplement but looking online am overwhelmed by all the different sorts. He has a lump on his front ankle joint, the vet said it's an old injury. He doesn't look like he's in pain yet but we took him to town on a damp day last week and while we were standing waiting to be served in the pet shop he lifted his leg. I give him cod liver oil every day which has made his coat glossy, just wondering if anything would help as a preventative measure rather than wait until he's old and stiff. He's 4.