So a while back (I can’t remember exactly when but I think it was some time around the 40s/50s), a bunch of penguins escaped. A keeper left the gate open so a bunch of penguins just… followed them. And the people loved it. Look at these adorable birds outside their cage just following that guy around! So they get all the penguins back inside and realise that none of them really ran off, they just followed the keeper and went back inside and crowd thought it was amazing, so why not make it a regular thing? Get enough people there that if one of them goes to make a run for it (which at least one has in the past), they can’t get past the people, and let the ones who want outside have a little wander. So every day, they get a crowd, they open the gate, and whatever penguins want to get out can go, waddle about, squawk at people, and then hop back inside.