Rats and Floor area of large coop

[Paige N]

I have a large (12x20) coop for my hens. They free range during the day (mostly unless we've seen a predator or I've got maintenance work going on). But we've got rats in the coop and I've got to keep them out! They're digging under the wire barriers and just being a nuisance.

So I've decided to cover the floor with hardware cloth wall to wall to keep them out. Trying to figure out what to put over the wire. Gravel? Just dirt? Pine shavings? A mixture? How to clean? What about scratching?

Am I overthinking this?

 

[aart]

They're digging under the wire barriers and just being a nuisance.

Some pics of the barriers might help.
Mesh on the floor will keep them away from the birds, but also kinda protect the rats.