I figure a new dropping every 20-30 minutes, so yeah they produce lots of waste. They are more efficient at digestion than let's say a cow, but they also do run hot and with a high surface area to volume rato, they have to eat to keep warm. Humans have to eat about 1500 kcal's to just sustain basic metabolic functioning. And my parakeets eat probably a 1/4 cup of seed between the three and produce easily 100-200 or so droppings a day depending on how much free flight time they get. (more free flight, more energy burned, more food eaten and wastes expelled) They are even smaller than chickens, run warmer, and thus have a high metabolic baseline to keep up via eating.