Please, please, please Twycross - go for Pertinax's option 1, and do it properly.
Move Bongo and Biddy in with the others and renovate the older gorilla house (enlarged paddocks with live trees and shrubs would be good). Choose a nice male, with the studbook keeper's help, and put him in Joe's old section, move the others back into their section and start the introductions.
Then put a wire roof on the newer gorilla paddock and add lots more climbing equipment for Jasongo and his group.
Alan
Move Bongo and Biddy in with the others and renovate the older gorilla house (enlarged paddocks with live trees and shrubs would be good). Choose a nice male, with the studbook keeper's help, and put him in Joe's old section, move the others back into their section and start the introductions.
Then put a wire roof on the newer gorilla paddock and add lots more climbing equipment for Jasongo and his group.
Alan