The Zoos I referenced are all accredited by the Association of Zoos and Aquariums. The vast majority of Zookeepers have a minimum of a bachelor's degree, and many have a masters. Zoos that are accredited by the AZA are required to participate in Species Survival Plans - science based programs that strive to maintain and create populations of animals that are genetically diverse and healthy, often with the goal of, or in support of, reintroduction programs. Most of the large, well known zoos have an entire division dedicated to wildlife conservation through science.
There are zoos that have failed to advance with the times, but they are pretty easy to spot.
"failed to advance with the times"
There are some very tried and true methods that still work....the flash of the advance is not always the awesomeness some promote....just my two cents worth