Get 2+ animals and give them a small space that they can keep warm such as a small wooden nestbox with lots of blankets and just one small hole. For heating-only you can get a small
4 watt animal heating pad
connected to a
probe thermostat
and set it to keep it around 65F in their nestbox. It is ok if their cage area is your kind of cold, just make sure that they have a warming place to sleep.
DO NOT get a heat rock or lamp or anything meant for non furry animals and do not use anything that is not controlled by a thermostat from within the confined space. These things absolutely get too hot and are not designed for furry animals.
There exist small digital thermoelectric brooders that can be set to maintain a temperature, say 70F, and you can forget about it. You could get one of these and drill a hole to use as a nestbox.
The
MR-148
is such a device but would be a bit large for just a couple of gliders. Plus I worry about the moving fan on both sides of the thing. Their small hands can reach inside the danger zone.
There exist smaller car cooler/warmers that use a metal plate inside to conduct the heat in place of a fan. But I have yet to see one with setpoint controls on it. Some of the cooler manufacturers can actually add that capability for a price. Koolatron has smaller thermoelectric coolers with the option for digital setpoint control. Medical carriers often use these to transfer body parts.
Some low voltage heating wire balled up inside of a false wall in a nestbox would keep the critters toasty. Just make sure to find some way to hav a setpoint thermostat on it. Can be a home AC thermostat or can be a mechanical style attic fan/pump heater type. Digital is better where possible and any form of this needs a temperature probe that you can stick inside of the space.
These little
personal fridge warmers
have the heatplate inside which is great and they are small but they have no setpoint control so you would have to add that via a thermostat and a probe. One of these would make a neat nestbox hanging outside of the cage using a feeder door.
Ive done that myself with a thermoelectric cooler and a home thermostat I happened to have on hand. I mounted the control outside for me but the temperature probe is inside of the container with the animal.
and I had an
earlier version
using a disposable foam cooler with a small animal heating pad and a probe thermostat.