I have my nesting box attached near the top of the cage, on the cooler side. I'm not worried about temperature b/c I take the eggs out right away and put them in the incubator. I put a little bit of sphagnum moss on the bottom of the box, which she doesn't really use and just pushes away, so basically, you don't have to put anything on the bottom.
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Lisa

1.0.0 P.m. grandis (Linus)
4.3.0 P. standingi (Toby & Kona and their 5 babies)