By Hal Walter At the starting line of the World Championship Pack-Burro Race in Fairplay, an ill-saddled donkey exploded bucking and kicking, causing a minor riot among the other animals and their humans waiting for the gun. On the other side of the street, another burro kicked out repeatedly in angst. My own burro tried to spin around in this chaos and head back through the crowded field, and in the process of getting her back under control she stepped on my foot, not exactly the best way to start a 29-mile race up and down a 13,000-foot mountain pass. ...