The cage soon needed changing, but catching mice to transfer them is as hard as picking up drops of mercury with your fingers.
Habitrail (TM) would do the trick but it's pretty dear for temporary pets.
Soda bottles make a cheap and robust set of skyways and nesting chambers.
Step 1: Cut a Hole in the Mesh Top.
Smaller than the bottle top.
I cut at the corner to make butting two cages together, but the bottles can go anywhere.
Step 2: Screw in the Bottle
Step 3: Cut a Hole in the Side of That Bottle
Cut a round hole about the size of the inside diameter of the bottle top.
Then cut a series of radial slits to about the outside diameter of the bottle top.
Step 4: Screw Bottle Into Bottle Side
I was going to glue this, but it didn't need it.
Step 5: Assemble Transfer Link.
and cutting the bottoms off of the horizontal bottles, a link is made between the cages.
Put the food and toys in the clean cage, and overnight, the mice explore and make their move.
Step 6: Mouse Nest in the Sky
Replace the open-ended bottle with a whole bottle. Melt about a hundred holes in the bottle with a skewer heated in a candle flame or alcohol burner flame. Add a couple of sheets of tissue paper, and the pent-mouse apartment in the sky is ready for occupancy.
Replace the bedding as necessary.