we've tried out these, machete loves them.
1/2 a treat a day, for his weight class. which should be about average for most corgis, i think it recommends 1/2 for the 1st 26 lbs. and then 1 whole treat for 27-50 lbs. or something like that.
they sell them at our local pet store, and also on amazon.
I've noticed this week that Katie, 9, is not bounding up the stairs quite as fast as she always has. Think my girl is finally slowing down just a tad. Joint supplements have been on my mind...I want her to be able to move free and easy. I think I may look into these.
I know there are a few liquid joint supplements, too. We got some joint health vitamin additives in one of our bark boxes, you add to your dog's water according to the dosage and it's supposed to help, too. I'll see if I can dig up the name.
I use Glycoflex 3 supplements for my older lab and they work really well, she loves them because they are meaty chews. I get them from petmeds.com and they have instructions for how many to give for the weight. She hasn't even needed her prescription meds since being on them.
I use Old Mother Hubbard from Petco. I call them his stinky treats. Basil loves them. They are his special treat (when he does something very special) but I make sure he does something special at least once a day. He's three, and has been taking them daily since he was one. More a maintenace/hopefully insurance type of thing.