This may be perfectly normal, but my last labrador never did this and I haven't seen it before. When my labrador walks his hind paws seem to swivel inwards. The paws land straight when it hits the ground, but once the leg is outstretched behind, the paw swivels inwards. It happens on both legs. He seems perfectly happy, and full of energy, so it may just be his conformation, but it looks weird. He's only 12 weeks old. Can anyone shine any light on it please?