Good idea - hadn’t thought of that.
The new bluebird house I put up has the feature of an elevated mesh floor which aids in the management of blowfly and other harmful insect infestation.
The new house also can be cleaned out between fledgling batches (and should be). The old derelict house was one my dad made with a pattern he got from somewhere - could not clean it out. The BBs still managed to raise fledglings in there, but it’s definitely better for them to be able to clean old, dirty nests out.
It was blowflies she mentioned it helping against.
I had never heard of them before she mentioned that.