I don't believe anything will dig under the foundation. if something does try, You will see evidence of it before it succeeds .
plug all holes in all the walls.
.......jiminwisc....
plug all holes in all the walls.
.......jiminwisc....
. Start by sketching out you floor layout for rabbit and quail separation . Think about how many you want to have . Then ask how much space is required for each bird and each rabbit . Use that as your guide . If the prevailing winds aren't blowing in the door opening then it can remain open. It's important to keep them dry so they will stay warm . Good luck with your project
Just stay at it and you'll get there .