DE will not treat an infestation of mites. Instead of typing all the directions ... I will refer you to these threads I have bookmarked...
https://www.backyardchickens.com/forum/viewtopic.php?id=208346
https://www.backyardchickens.com/forum/viewtopic.php?id=226143
https://www.backyardchickens.com/forum/viewtopic.php?pid=2525157#p2525157
https://www.backyardchickens.com/forum/viewtopic.php?id=208346
https://www.backyardchickens.com/forum/viewtopic.php?id=226143
https://www.backyardchickens.com/forum/viewtopic.php?pid=2525157#p2525157