I goofed. I went in to the pen with Twinkle and Riley to feed them. Then, changing routine on the spur of the moment, I went from their pen into the south yard and fed Brigus, Barley, Bianca, and Woody. When I retraced my route back into the south puppy pen I discovered an open gate and empty pen. They came home quite soon without getting into serious trouble. Now I remind myself that I am dealing with clever young animals who, at six months of age, will try anything.