Get yourself some Ravap EC/ Permectrin II, or Atroban 11% EC and a yard and garden sprayer. Remove the birds from the coop and don't give them access to it while doing this. Clean out all coop litter from floors and nests. Either bag the old shavings or put them in a garbage can where you can haul it out and dump it in a field, then spray the heck out of it, or spray it with the mixed product in large construction waste bags, and haul it to the landfill. Shop Vac or sweep out dust. The product will be mixed according to label directions in your sprayer, and follow safety guidelines. Spray down the coop focusing on all cracks, crevices, under, on top, and sides of roosts, floors, walls, nest boxes, and yes, even the ceiling. Let the product dry. Laying a leaf blower at the entrance to blow in the coop will dry it quicker. Otherwise just leave all windows open and let it air out.
When product has dried, lay new shavings on the coop floor and nests and you can let treated birds back in the coop. All those products mentioned above can also be used directly on the birds. Here is a link for more info:
Edited by Michael Apple - 1/2/15 at 6:10am