Good idea, and great principle of the solution being within the problem.
I tried that (leaving trapped mice in with my
chickens) but they got to smelling pretty bad. Of
course I have commercial lay pellets out all the time, so they never get too hungry. We have a group here in CA called "Project Purr" that catches, neuters, and then adopts out feral cats. They brought me three, two stayed, and they take out many mice and rats, only occasionally a bird. When I do catch a mouse or rat in a trap in the
chicken coop, it serves as a treat for them.
Don Eggleston