Doesn't matter what age a pup is if they leap off a deck and injure their legs. I would have your vet check out his limping, he may be in pain.
When Cody was 4 years old he was fence racing with two chihuahua's for about 30 minutes. All that activity that he wasn't use to ended up with him injuring his legs. I took him to the vet, they gave him pain killer and muscle relaxer.
Last year Cody was 9, he was chasing something on the deck, dashing in and out of low steps, he ended up with a back injury, off to the vet we went.
__________________ Joan, mom to Cody  RIP Matese  Schnae  Kajon  Kia  forever in my  A House Is Not A Home Without A Dog |