Thanks guys! I'm completely enchanted by these two little creatures. To update you on their progress, they're putting on crazy amounts of weight: they've put on about 20g each in their first week! I think they're trying to scare me to death with their daredevil antics, I've had to rearrange the cage a few times as they discover flaws in the safety that I wouldn't have considered. For example, it's a tall cage and I had taken all the levels out. I thought there was no way they could come to harm as there's nothing for them to jump on but one evening, I noticed peanuts hanging out of the roof of the cage- he'd completely scaled it! I managed to catch him before he fell but I'm sure he would have hurt himself. It's safe now, thankfully as the other lad has started scaling the small height available too. In general, I'm a bit nervous and unsure about everything- they seem very fragile and completely reckless! They're pretty slippery now and catching them to weigh them is rather tough if they don't want to be caught!!
I could do with some advice about the flooring though, at the moment, it's fine mesh packed with sawdust. I've heard mesh can be dangerous for chinchilla feet, particularly kits. What flooring does everyone else use?
Appreciate all your feedback very much
More photos of their progress to follow.