DH calls that pre-seasoning the chicken.Glad they got to you in what sounds like good condition! Keep us updated.
I made a dust bath for the girls and mixed in about 40 lbs of sand, about a cup of food grade DE, and a cup of these lovely smelling dried herbs. Probably do nothing really but they smell so nice. Just like a fresh bottle of poultry seasoning...I have to wonder if that is a deliberate troll and the makers laugh their butts off or a coincidence? You decide.
I have the same problem. I leave it out for them and they tend to ignore it even when they are laying thin shelled eggs. So, sometimes I sprinkle it over their egg layer pellets ( which I know you aren't supposed to do).