Can I make some suggestions about cage set up if you're using the same cage
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After many years of setting up cages, I've found ways to make them safer if they're a bit on the tall side. You're limited by the glass base size as to how much bedding can be put in, so another way to avoid fall risks from a height is if you fix both the shelves to the roof at roof level. This effectively means you've blocked off the roof so it can't be accessed for monkey barring. I have often done this with an older hamster as well, when their platforms need removing but they still like the overhead cover of a platform.
The shelves at different levels, as they were before, along with the height, mean a hamster falling from the roof could land on a hard ladder on the way down or bounce off the edge of a shelf and hurt themselves. We just don't see what they get up to at night!
So my suggestion for setting up your cage would be to fix both the black shelves right up against the roof, and not use them as shelves.
You could get a nice multiroom house with a flat roof that makes an alternative platform and encourages normal behaviours - nesting and hoarding in different rooms. And maybe another platform as well. I know that means buying extra things - but you could actually just make a shoebox house rather than buy one. You cut the base out of a shoebox and keep the lid as a lift off roof and cut a hole in the side of the box for a door. They really like a nice large house that's dark inside.
You can get all kinds of nice platforms now and as you have the lovely glass square base, they would fit well. Hamsters are ground dwellers really and like digging and foraging and they are very bad with heights. They are not natural climbers. They will climb, but they're not good at getting down again and don't see well and they tend to just drop. They can climb bars right to the roof and monkey bar across the roof and drop the full height of the cage.
If he can't get to the roof then the rest of the set up is safe for the hamster
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