here is a few articles that say just the opposite, of course, all in moderation.
My scaley leg-mite "roost rub" does have moderation, and is made from a gallon of either crisco or lard, so there is not enough essential oils to harm any bird & I and many others have followed this "recipe" for...
OBTW:
You know what NEEM Oil is, and the reason it works good with the Sevin is that it is an oil, which smothers the mites,
"Melafix" was easy to find, pure tea tree oil we use(d) for our koi that had fungal issues. This tea tree oil is extremely concentrated.
Don't go buy tea tree oil for...
Sevin dust...hold the bird down (at night is best & wear a dust mask on your face) and dust the bird...rub it in all over them, and repeat on every bird in the coop & do repeat in 6-7 days in cold temps, or 3-4 days in hot days.
GOOP : a tub of Crisco or lard on roosts, I add 3 T of NEEM oil...