My experience, after many hours of misery, is that - no matter what else you do - if the paths around the exhibit are busy with guests (ie: crowded), the animals will be stressed. I have bongos and tortoises and they're fine - but they're both on less traveled paths. My flamingos, usually very tolerant, are in a central location with paths on all sides of their exhibits. There's plenty of shelters and etc but every time it gets crowded in the zoo, they get stressed. My jaguars, shy animals, are usually okay because their habitat is on a less busy area - though when the place gets crowded, they get stressed for awhile. Basically, the only solution I've found is to have the animals off whatever the main drag of your zoo is.