The world's supply of pule comes from a single herd of Balkan donkeys that live on a farm in the Zasavica Special Nature Preserve, Serbia. Part of the reason this cheese is so expensive is that donkeys don't yield too much milk, and they all have to be milked by hand, three times a day. Apparently, 15 donkeys yield about a gallon of milk, and it takes 3.5 gallons to make a pound of pule cheese. The donkeys of the Zasavica Special Nature Preserve only produce enough milk to make around 200 pounds of pule cheese a year, which makes it very hard to come by.
