The penguins from Batman Returns had their own luxury swimming pool!

Additionally, they had half a ton of ice and fresh fish delivered daily. Needless to say, no penguins were harmed in the making of this movie! In fact, the animals’ comfort was prioritized above the humans; the plane on which they all flew over was refrigerated down to 45 degrees F, and the entire set to 35 degrees F. 

During shooting, 50% of the Warner Bros. property was occupied by the Gotham City sets. The penguins and Penguin shot their scenes in Universal’s Stage 5, which was transformed Penguin’s underground lair. 

A half-a-million gallon tank filled with water was used for the penguins’ comfort. Production went smoothly for the most part, but there was a brief moment when they were interrupted by protests from Animal rights groups after they discovered the penguins would have rockets strapped to their backs. 

(Source)