glad to have you join us.
Never thought about "treating" the building site. Interested in seeing if anyone offers opines, but would not consider it unless you know you have an existing problem there. And realize that any pesticide is only temporary.
But IMO the best way to help prevent external pests is to try to keep the wild birds away from the chickens and provide ample dust bathing area. And examine your flock members routinely and act at the first sign for treatment.
If you feed or attract wild birds, place the feeders remotely away, on another side of your house would be best.
If you add to an existing flock isolate the newbies and make sure they have no pests or disease before introduction.
To help avoid attracting squirrels, mice, rats, snakes - build the coop elevated and cover all "cracks" or windows with hardware cloth. Keep the bulk chicken food indoors or in a water tight secured bin.
Use hung feeders and founts to deter ants. Monitor in and around the coop/run for ants and treat mounds outside the compound.
Routine non-pest bugs will be handled by the chickens - their favorite past-time. Except my gals don't care too much for ants :)