Basically, these are just little houses I made for my mice for birthing. I have no idea if they'll use them or not though. The specs on these in case anyone wants to make them: standard cardboard, 6 pieces that are 3 1/2" by 3 1/2", and masking tape to tape it all together.
This is the one I just finished. It's still a bit messy, but I figure the mice don't care what it looks like as long as it's secure.
Prototype being testing. Test subject off camera stuffing her face :| The prototype was made out of the same materials plus elmers paper glue. I decided to cut that from my next house due to how time consuming and messy it was.