Hey there just saw your post and thought i'd give my 2 cents worth. I have 2 3yr old snake neck turtles and i was told by a vet that cannot survive a new zealand winter even if they hibernate during the cold winter, they will struggle in the summer also as they can get a chill and get pneumonia once they get this there is no treatment for them they will die within a few days to a week. having said that i live in Christchurch so it gets cold down here, they might be ok if you live in and above Auckland they might be ok outside for the summer. i also have found if you feed them on feeder fish they have more energy and they grow quicker, i assume the feeder fish have alot more vitamins and minerals than bloodworms etc, i also give them meals worms as a treat, give them a varied diet is always good i have also given them frogs, tadpoles, mince meat, venison, beef, fish from fish shop, dead mouse or two (just to give them a challenge for food very interesting with a dead mouse...makes a mess to). sometimes i will put them into my 1000 liter tropical tank for a decent swim, followed by a few hour run around either outside or in the lounge.
other than that i love these two and hope i have a long time with them.
Thanks.