can't get enough viewing gallery money
Guests like large enclosures with many baby animals; put in a few trees and rocks, and have popular rides and food stands nearby. A large enclosure with elephants, giraffes, and zebras will have guests lined up to pay $9/person.
Kangaroos are popular but don't like other animals in the enclosure. Pandas are solitary so two might be happy in a large space, but guests won't pay much to view that.
And have plenty of keepers, guests are turned off by piles of manure around the place.