On the second floor, I had two zoos arranged with a narrow room between them; some 165 creatures all told. When you can see one tile of one zoo, you can see all tiles of both zoos. Therefore, I was able to stand back and just cast magic into the second zoo to kill all it's inhabitants without having to open it's doors. Secondly, I didn't get any bloody rewards from the zoos. The monster counter didn't decrement. All the best, --DDR