Mary, as far as i'm aware of Sevin or Carbaryl has never been an approved treatment for chicken mites in this country although it is still an approved treatment in other countries.Carbaryl is no longer approved for chickens here, so I'd avoid it.
Mary
There is a long list of treatments for chicken mites that have come and gone over the years all the way from Black Leaf 40 to Sevin. The same is true of worm medicine. Every time a treatment proves either safe or effective the Animal Rights organizations raise objections because in my opinion (with good evidence) these organizations would rather see every chicken on Earth die a painful and lingering death than see one chicken baked, boiled, broiled, fried, or fricasseed.