The youngest babies are 5 weeks old and made their first venture out into the upstairs living room. They were closely supervised because they don't know anything about stairs yet and were getting their first taste of the wide open spaces.
Here's Viggo (rear) and Vin (front) with Doc lounging in the background avoiding the camera flash
This is Viggo doing exactly what he wasn't supposed to - heading for the stairs
He was scooped up and brought back - much to his dismay