We have a Collie Lab mix that is about 8 yrs old she has been limping on ber rear right leg for about 2 months. She dosnt act like she is in pain ie. when touched, petting or rubbing her paws. We have taken her to the vet no Dysplasia, mass or breaks possibly some arthritis but other than that nothing obvious. The thing is when she wants to she will still run and seems like she is using that leg and when she jumps she seems to launch off her back legs fine. We have started giving her hip and joint supplements. We just hate we cant figure out what to do next any suggestions???????