treating a hen house

Try spraying with ficam w it's available online. It soaks into the timber and will give protection against red mite all summer. But do follow the safety precautions because it is really strong stuff. I application sachet will make 5 L enough to treat a good sized shed

If you can do it early on a warm / Hot day so it drys out quickly you might get away with it in one day. It's best really to leave it 24hrs to completely dry out before putting birds back in. make sure you do every crack, nook, and crannie, it's amazing where they can hide. A pump spay works best and is quicker, but a good hand held spay works as well. Follow the safety info though because It's really amazing stuff and gives lasting protection.

Thank you Joyfull. I use DE on my small hen house . Do you know how to make aDiatom slurry & what the quantities would be?

I used  Cuprinol on my to weather proof it, then once a week I clean it out with Jeyes fluid, scrub the floors and walls, meanwhile the hens are making a feast of the grass and flowers, it dries in about an hour

So far never suffered from any red mites or any other bugs (and it keeps the flies down)