2017's big addition to My Free Zoo was the Zoological Society, which is a fancy way of saying additional zoos. The Love Zoo was released June 7, 2017; the Serengeti was released Sep. 13. At that rate, the next one - Farm or Prehistoric - will come out around Christmas. January seems more likely to me.
Opening the Zoological Society
You have to pay...what, 150 diamonds to unlock the Zoological Society at all. After that you can unlock new zoos in whatever order you want.
Additional zoos:
- The Zoo D'Amour (June 7 2017)
- Serengeti (Sep 13 2017, 3 months later)
-Prehistoric Park (May 2 2018, 7.5 months later)
-Menagerie (Oct 17 2018, six months later)
- The Farm (November 28 2018, just a month later, whoo)
Other planned zoos:
-Pelagial (this means ocean)
What About Employees?
Bad news: your employees will not go to these zoos on their own (as they do with the museum). You'll have to assign an employee to it - not just a member of a team, either, that won't work. And they'll need paths - functional ones, so they can get to whatever they're caring for. Employees are a problem.