I have lost 2 chicks and one adult got respiratory illness from wood ash. I'm not saying no one should use it, I am just putting it out there that it can cause problems. More so in very young chicks who sleep under a broody that has dusted in wood ash. I never ever use DE in dust baths. I rarely use DE at all. My chickens get coarse sand and the dirt around their coops for dust bathing, and we keep their coops clean. If there is an incidence of lice or mites, we have used poultry dust, but I am now going to use something else because it has caused respiratory issues also. I might add that the only chickens I have encountered issues with are silkies. My large fowl flock doesn't seem to be bothered by ash, DE, or poultry dust.