As mentioned above, zoos indeed have a different agenda. But it most cases, its about display value. Its rare you will find a bank of heat lamps in the viewable part of a cage. Ruins the effect. Also, artisticlly speaking, a short cage is not very viewable, so most reptile displays are very tall, this means heating elements are very far from the animal. Therefore, the old dehydration problem is common, only on a very large scale.
On the other hand, I worked on an outdoor Gorilla enclosure, that did have a viewable heat bank for gorillas.
The main concern I have with that pic is, the forarms look a little like there may be some calicum def. going on. I would have that checked.
If your thinking zoos should be a guide for private keepers, they are not and should not be. As mentioned, their goals are different. Also, they are very much like the general public. some are great, some good, some not so good, and some suck. That is common and general and hard to escape. FR