Just keep in mind that if you choose to use it, you would not use pure Sevin in the dust bath. (You wrote that someone told you to put "a pan full" of the dust--ack!!!!) You would just put a handful or two in the dusting area, or mix a bit in with sand, wood ash, etc.. It would make a small part of the dust bath, not the whole thing.
To keep them from ingesting any Sevin, make sure to put it in a dust bath that is far from any greens they eat. My chickens kick up a storm when they dustbathe, for instance, and the dust coats the plants and grass around the "bath." Then they pick at and eat that grass. If it's just dirt and DE in the bath, this isn't a problem. If it's a poison like carbaryl (Sevin) or permethrins/ pyrethrum, it's a very bad idea.
To keep them from ingesting any Sevin, make sure to put it in a dust bath that is far from any greens they eat. My chickens kick up a storm when they dustbathe, for instance, and the dust coats the plants and grass around the "bath." Then they pick at and eat that grass. If it's just dirt and DE in the bath, this isn't a problem. If it's a poison like carbaryl (Sevin) or permethrins/ pyrethrum, it's a very bad idea.