As part of the concept team at PGAV that developed Glacier Run with Louisville Zoo, I am excitedly awaiting the opening of Phase 3 of Glacier Run--the Polar Bear, Sea Lion, Sea Otter, and Stellar's Sea Eagle exhibits. However, since phase 3 is still not under construction yet due to lack of funding (get on their webpage and donate people!), we'll have to enjoy the opening of a refurbished Siberian Tiger exhibit nearby the site.
Phase 1 of the exhibit area, a themed water play area, was opened last summer, and has since been packed with visitors daily. Phase 2, the tiger renovations, included updating the mid-century enclosure to be more visitor and keeper friendly. The old exhibit was uninviting, having 15' tall concrete walls all along the public walkway. The viewing area looked like a bunker. Now, the visitor area has been softened with pergolas and plantings. Training panels have been added so the public can get a first-hand view of the extensive behavioral training and enrichment the zoo conducts with its tigers.
In fact, Louisville Zoo is on the forefront of animal training and has a tradition of building enrichment and training opportunities into exhibits as a major component (see the Islands exhibit). The Zoo's philosophy is to turn the zoo "inside out" so all visitors can clearly see the extraordinary care given to the animals by the staff.
In Phase 3, you'll see much of the same. In concept development, the staff's first concern was to make the environment as complex and enriching as possible with the small amount of space available to the exhibit. This created not only a complex exhibit, but also a complex holding and enrichment facility with tunnels, stairs, a foraging room, and a maze of transfer chutes. In the final design, most of these elements made it, enriching not only the animals' lives but also the enhancing the experience for the visitors.
The new Glacier Run exhibit area will replace the current mid-century polar bear exhibit, and take over the adjacent hillside. The old exhibit was an excellent example of modernist design infiltrating zoos. The exhibit was more of a sculputural piece than a proper animal enclosure, and the animals were clearly affected. Stereotypy was seen, and animals rarely used their pool. The exhibit was entirely concrete with no natural substrates whatsoever. The new exhibit will be greatly appreciated by the bears.
Check out the Louisville Zoo's Capital Campaign page for extensive information on the upcoming exhibit, and ways to contribute.
Generally, we've been incorporating some sort of rotation capability in all of our exhibits for the past several years. If the staff is willing, the advantage is great: providing several smaller exhibits in which to rotate through the animals during the day provides active animals, which in turn, provides engaged guests. 
