There are certain zoos in the world that should be shutdown due to animal welfare and they are just profiting from the visitors - these are what I call 'circus' zoos, yet some zoos are doing 'good' in terms of educating the young and researching. Animals should be in similar environments to their own natural habitat and should be given a lot of space to move around, but unless you are at a safari park style zoo, this wouldn't happen.
Btw, @scottdphoto, great post and photos.