I was sold my first (wooden tongue & groove) coop, 2nd hand, by a local poultry farm & fortunately learned before I got my first hens that the coop was riddled with red mite. By the time I'd used the Total Mite Kill on it, it was fine. Thereafter whenever I cleaned it I'd dust the inside with diatomaceous earth powder. (FFP3 mask of equivalent strongly recommended for this.)