I'm looking for a bit of advice about my Prevue Ferret Cage for my rats: https://www.amazon.ca/Prevue-Hendryx.../dp/B000QFMYWQ

The older two males live below, separated from the younger two males above. They also all have a large playpen in the room that they get to use in pairs 1-2 times per day for play and running around.

I also have a not in use Kaytee Exotics cage: https://www.amazon.ca/Kaytee-Habitat.../dp/B00CETSHN2

I've considered taking the top of that cage and securing it to the top of my Prevue cage since there is a door at the top of the Prevue that can be left open. This makes the whole cage massive, and would be secured in a room corner.

This would allow the younger two males to have the top of the Prevue and the entire Kaytee cage above (minus the plastic tray).

I don't want to limit my older two rats below too much, they do get handled and playpen time each day, but this would be a kind of back up to if the introductions to the 4 of them doesn't go well. It'd also make it super big and lots of vertical space to play and sleep.

Does anyone have any suggestions or advice about a modification like this? IMG_5923.jpg
I'll see about rotating future images....