Zoo scene- help me find this book please

[Stacey]

I have a vivid image in my mind of people, possibly children in an open bar zoo.
Rich people observe them.
Some escape or are rescued.
May have magical powers.
Currently watching Hunger Games and I was reminded of this book, but don’t recall much else.
Probably YA

[Kris]

Stacey, please add genre (e.g., YA fantasy, dystopia, horror?) and plot details to your header. All headers must contain this information, since many of our members only scan the headers.

You can copy and paste from what you've already written. Click the small "edit" link after the header. (This only works on the full Desktop website - not the Mobile website or app. If you're using the Mobile website, click the "Desktop version" link at the bottom of the page.)

[Florence]

I think there’s a scene like this in one of the Mary poppins series (possibly the second one)