Sheep with a border collie in England (© Wayne Hutchinson/Minden Pictures)

【September 30 2014】Scientists believe that the sheep was likely one of the first animals to be domesticated by humans. Most sheep still graze freely, unlike cattle, hogs, and chickens, which are fed concentrated grain diets designed to increase growth and health. Estimates put the global domestic sheep population at 1 billion.Explore breathtaking Gallery from the HuluTrip homepage over the past 5 years..