Hi Helen. Are there any seed mixes available in NZ specifically for quail? Mostly such mixes here are sold mainly for coturnix quail, raised fir their eggs, Yes they do need a relatively high protein diet compared with chickens, and I think perhaps your best bet might be to search the internet for articles on feeding, and on other things they need such as suitably small- sized grit, such as this one which might be useful.
https://www.thehappychickencoop.com/quail-feed-and-diet/
Keeping button quail isn’t very common, at least in the UK, although if you search the archive of this section of Poultrykeeper you will find quite a lot of posts which might interest you about care and management. They certainly are amazing little birds. I do think that your male would be happier with two females, if possible, and this might reduce the demands on a single hen once the breeding season gets under way.
What sort of run have you got for them, and can they go outdoors in a run on grass in suitable weather? Any outdoor ranging you can offer will help to supplement their diet with high-protein bugs and other treats.
Some pics of them would be lovely. The forum software isn’t the most modern but here’s how to do it. http://poultrykeeperforum.com/viewtopic.php?t=11259
