During our walk this morning with Paisley we noticed Zack was hopping along on his right hind leg on and off. He has occasionally done this since he was young and I have had his knee caps checked several times and have been advised they were just fine each time. It is weird as Zack is not lame, walks just fine, runs, jumps nothing seems to hurt, but he hops sporadically on that same leg only when we are out for a walk. It doesn't happen in the house. However today he was hopping more than usual so off we went to the vet again to make sure nothing else was going on. After a thorough exam Zack's knees were given the all clear but he was a little sore on the top of his right hind leg/ hip when she pushed he flinched. To cut a long story short Zack's vet thinks that he has a bit of an ache from where he had his bone marrow biopsy done when he was a sickly puppy (which thank god came back negative for leukaemia) she advised any time bones are messed with in any way it can cause aches in the future so she thinks that his odd hopping all this time and more today is from that. It certainly makes sense and the extra exercise he has been getting with me on holidays and the cold weather probably didn't help either - poor boy.
It is not serious but something we may have to live with and if it becomes really bad just give Zack some pain relief but for now just some R & R.