How can i stop my puppy eating his poo?

My 6month old husky x german shepard keeps eating his poo in the garden.I scoop it up as often as i can but as soon as he do`s a number 2 he turns round and sniffs it then munches on it how can i stop him doing this? I feed him plenty of dog food 3 times a day so he`s not hungry and is the correct weight for his age.