Help for older Russian dwarfs struggling with tubes

[Chrisssy]

Hi all.

My older hammies are struggling with the tubes in their cages. Is there anything I can do to help them climb - or improve the set up for them as they get on in life?

Suggestions welcomed🙏

Note: I originally had a group of 4, P@H assured me they would all get on - but after a few months they fought & 2 are now in this set up. I know not ideal but I didn't have the space