This is a demonstration piece, where you can see a real penguin egg versus a wooden one, that they use to fool penguins (and all other birds). Often times, if there are problems, they will remove the egg from the mother and take it to their incubation chamber. They replace the egg with a wooden one while this happens, so the mother isn't upset. One bird at the zoo currently sits on 13 eggs. 5 of them are wood, as the real ones were not fertile despite attempts to incubate them.