Do chickens always have lice? even after treatment?

[LindsayB]

i noticed last week all 3 of my hens had lice on them so I dusted them with poultry dust that kills lice, fleas, and mites. I dusted the whole coop as well (except for the nest box) and re-dusted eveything and them 6 days later. I'm still noticing a few lice on them though. their feathers look great so I dont see how the remaining lice are bothering them. Are chickens just always going to have some lice on them?????

 

[Three Cedars Silkies]

You have to keep treating until all the lice/mites are gone. The lice eggs hatch daily and you must keep at it until all are hatched and dead.