Both the rarer kiwi (Little Spotted & Okarito) as well as the saddlebacks and many other NZ species are already managed very intensively by the NZ Department of Conservation, to such an extent that for some species it basically reflects zoo practices with studbooks, transfers between different locations etc. For now there is no overcapacity and NZ zoos already collaborate with DoC on these programs (e.g. Saddlebacks in Auckland zoo are surplus stock from the "wild"). There is no need for zoos overseas to get involved here and the laws with regards to exporting animals from NZ, especially reptiles, are very very strict.
Please check and adapt it before you post, your longer posts can be hard to follow due to all the typos.
i do know of the work by the DoC and am aware that it works conservation wise but the reason why i mentioned a captive breeding programme brings up two the reason why animals are kept in captivity back up population to minimize the threat the species face in wild both invasive predators with only of shore islands and fenced island like areas being small and therefor prone to other natural disasters the second reason is educational purpose
like u mentioned they are kept in captivity and it is a whole conversation on its own which and when species should be kept in captivity
tho i would like to mention two things
i read how nz tries to deal with the threat their enviorment faces and their awareness thry could not safe all species and therefor developed an algorism calculating simplified the value of species
what made me immediately think that those species sort of sacrifieced could be rather exported
the laws are man made and like i mentioned before arguable
yet since this thread is about the potential expansion aka new species kept worldwide less likely
the second thing i wanted mentioned was something a keeper working at kiwi center in nz said in a documentary and that was they were chronically underfunded and relied on volnutary work and otherwise could not safe the same number of chicks
i do not know what the name of the documentary was since back then i did picture myself ever using that information
therefor i can not say if this representative but i think they mentioned they were the biggest and due that most relevant hatchery for kiwis
i followed how auckland tried to get orange fronted parakeets and the saddlebacks and it seem quiet difficult and i asked myself a bit how well and tight the conservation department and the public institutions work together
i do not know how normal it is for a native to see certain species and what part they play in the kiwi culture but i expected a bit more representation what equally applies to australia
also a bit for the oversea terrtories of the uk maybe even other countries