All winter with no heat in Melb? What sort of hides do they have? What months do they feed, when do you stop feeding? Are you ever concerned it is too cold? Sorry for all the questions but I am not sure what to do with mine, where I live is colder than their natural temps and I'm a little concerned about turning down the heat and it being too cold.
Yes ever since they've been outside (I have a male and two females) they have had no heating at all. They have a large polystyrene hide box but rarely use it. They either curl up on the floor of the aviary or elevated on a branch. I'd say that they use the hide box fewer than 10 days over winter, but use it regularly in summer. Anything over about 25 degrees and they disappear.
Typically they emerge from being coiled up at night in a corner somewhere, find a sunny spot and bask. In summer or warm days, basking rarely goes on for more than a couple of hours. They then seek a shady spot until late afternoon-early evening when they become active again.
I feed until around now (all three fed last weekend) and I'll start to feed them again in late August - early September when we get a warm spell. I'm not too concerned about this. Do you think a Diamond thinks to itself "I'd better pass up that bandicoot, its getting cooler and I might end up with a guts ache and die." You'd be surprised how warm they can get with just a little basking so I think they can metabolise meals without too much concern in cooler weather.
My larger female bred two years ago, laying 16 eggs.
They are in an aviary that faces east, with a roof that only covers 2/3 of the aviary so they can always find a basing position....they are active constantly thermoregulating. I know several keepers who run with variants on this theme, a couple run supplementary basking lights some don't. Diamond Pythons extend as far south as East Gippsland in Victoria where the climate is marginally milder than Melbourne, but not much. Some years would see colder, longer winters than others. I am absolutely convinced that this is the way to keep Diamonds - time will tell.
I'd be surprised if other keepers who keep their Diamonds outside would have experiences too different to mine. By the way a friend of mine kept a Port Mac intergrade diamond/carpet this way for many years in Melbourne around 30 years ago!
Here's some pics of my animals.