each year we also kill about 2.5 billion ducks , 1.5 billion pigswe allow pigs a life of about 6 months , nice of us1 billion rabbits , 800 million turkeys , 600 million geese , 600 million sheep , 400 million goats , 350 million cows and their children , 80 million rodents , 80 million birds , 20 million dogs , 9 million horses and donkeys , 5 million cats , and so on .