Gee I would think wood would do it. Mine was open and we put the wavy on it. That's why we took it off and put the wire on. But we only have Rats and Opposum to contend with.
I had to come back and see. Your girls look so happy in there. Bright eyes and happy dances.
18 sq ft = 18 Coturnix, maybe 20. Would make for a nice size Communal breeding pen. With, oh, a 1Male/4 or 5 Female ratio. Might be some scruffles at first so, keep the old pen for when you add more. Take these girls out for a while. Put them in with new into a different pen or pens. I think they say for a week or 2. (can check old threads to be sure). Rearrange this pen, just move things around a bit and then put everyone into this pen. Should work with little fuss after that.
Coturnix and other birds can be little ruffians. Can and will draw blood when fighting. Can and will kill each other at times. So play it safe. I have culled my share of very bloodied birds getting them into the group that they liked. Some people don't have a problem with integrating the birds, but others do. Depends on the birds.
My first, are what 15 weeks, and are just now settling down. And it's time to move them to different pens. OY.
Nice, enjoy. Once they settle in, you'll get to hear the singing when you bring them food, water, treats. Happy Wistles. The cool part of raising these little ones. Until the day they scare the begewilabies out of you doing their calls all at once, when you are working just outside of their pen.
Happened today. Every Roo of every age in my back yard trying to out yell each other.