all small breed dogs poop a lot and often, their digestive tracts are short. My fully grown 4lb adult chihuahua goes 4 times a day. if you feed him less, he will get very skinny, will have growth problems, and may die. feed him the exact he should have, you should invest in a pair of scales. if you cant deal with the pooping, rehome him, and get an adult large breed dog who will only need to go once a day.