Transhumance is the seasonal migration of grazing animals between winter and summer pastures. It is an ancient tradition throughout the world, and one of the last truly natural and sustainable models of livestock farming in existence today. The numbers of sheep farmers who practice transhumance today are in decline, and of those that still do, most transport their sheep by lorry. However, some herders still walk their flocks along roads and the ancient transhumance paths of their ancestors, on the slow journey up to high-altitude grazing land. Every June, organic sheep farmer Jean-Philippe Girod walks for 3 days and nights with his shepherds, friends, family and over 600 sheep, from his farm to fresh, green pastures in the French Alps.