Vickischics
Life, is a Learning curve.
Is that DE sprinkled everywhere?I’m not sure what the culprit could be here. Roosts are quite low, everything is well cleaned, bedding is cushioned. Here’s a pic of the inside of the coop. Everyone is healthy weight and adequate nutrition. We do have pine trees over the coop so maybe the cones and needles?
If so, please wear protective Eyewear and gloves. It containes very fine particles that go air bound and will enter your lungs plus it can affect your Chickens lungs.
For it to work, the bug must stay coated in the white powder to die otherwise, it does not work for bugs in the coop or on your girls. What works extremely well is Permethrin. It's much more effective for mites and lice. It also has a 28-30 day dry effectiveness to it.
Sand and make smooth all your wood pieces that your chickens touch.
Good luck!