nick sheridan's been to find out why.the outer hebrides — a rugged rib of islands off the west coast of scotland. rearing cattle here on harris and lewis comes with its own set of unique challenges. one of those is fencing. it takes time and money to install and maintain. it's vulnerable to the elements, and wildlife can easily become trapped in it. if a cow really wants to get through or over a fence, they're going to do it. that's the main risk, i think, from my point of view, they're going to escape it, they're going to be... they're going to get hurt, they're going to go out on the road. an innovative new piece of agritech has seemingly solved donald's problems. norwegian company nofence has developed a smartphone app that allows a farmer to draw invisible virtual fences. these can be created and changed in a matter of seconds, from the field, to the couch, or in donald's case, from his bed. the app then communicates with gps—enabled collars worn by donald's highland cows so it knows where they are at all times. i'm i