Two of three species of turaco I saw within this aviary, the third being Great Blue Turaco. Not 100% sure on ID of these green turacos, think two may be Livingstone's Turaco?
The one on the left is a Hartlaub's, the two on the right are indeed Livingstone's. Besides the Great Blue, there are also White-cheeked and White-crested turacos in the same aviary.
Thanks @Zooish! Five seems like a very high number of turaco species to keep together, in a not especially big aviary (by Jurong standards). Were the turacos all removed from the Waterfall Aviary?