What kind of dog is he? I have a Great Dane that I rescued at 2 years old. I put him on a joint supplement as soon as I got him. I had to up his dose as he got older when I noticed his joints starting to pop when he got up. The vet just diagnosed him with arthritis (he’s 7.5 now). I tried switching joint supplements once and his joint popping got really bad- the new supplement wasn’t working well. When I switched back to the old supplement the popping stopped. So that was a long way around telling you that it could be a joint problem. He might benefit from a joint supplement (something with glucosamine and chondroitin). I also have a pit bull in the house that does that stretching you are referring to. He does it ALL the time. I thought it was just a personality quirk. He’s 5 yrs old and 70 pounds and his joints never pop.
If you are really worried, you could take him to the vet and have them do an xray to see if there are joint issues going on.
