[Eire_Ade]

Although I don't keep Leopards myself, your problem keeping the greenhouse warm in winter is a practicle one I might be able to advise with.

I would make a warm box for inside the greenhouse a bit like a tortoise kennel type mini shed set up, with access to the cooler part of the greenhouse to thermoregulate much the same as Sandy advised.

You could also line the greeenhouse with polstryrene insulation from builders merchants on the glass walls to stop as much heat loss as possible.

Remember its easier to keep smaller areas hot than bit open spaces so sub divide the greenhouse up almost into rooms for hot, warm and cool areas.

Hope this of some help to you. And also well done for being a foster Mum.

Ade