Everyones birds are different. If it works for you then thats great. Some people have a LOT of chickens and generally DE doesnt work for them because they can get overly infested. I have 8 birds and the DE combined with wood ash seems to work for me. So im going to keep doing it regardless...
I use a combination of de and wood ash to prevent mites and lice. Thus far i have not had an issue with either but that is not to say i wont use chemicals if it becomes an issue. I used to watch a video blog on youtube about raising chickens and she has since lost my viewership due to claims...