Iāve read that wood ash is good for dust baths. I donāt burn wood any more, so I havenāt tried it. Iād think that if it were too caustic thereād be loads of folks saying, āWhatever you do, donāt use wood ash.ā
One thing about dust bathsāin nature they would happen out of doors. If the girls are confined a lot of time in winter, itās nice for them to be able to do their ablutions in the coop and that does require actual dust. We all have to make compromises. I guess Iād say to maybe save the ash for outdoor bathing. It IS really caustic, (which is probably the reason itās good for getting rid of pests), so Iād be concerned about lung irritation. OTOH, people do use it and I havenāt seen anyone warning against it.
I put some diatomaceous earth in a dust bath in the coop and wish I hadnāt. It poofed up everywhere. IF winter EVER ends, Iām going to pressure wash the coop and never ever use that again. But chickens do bathe in coop, in dusty stuff and appear to do all right. Really, they seem perfectly satisfied to use the deep litter for their dust baths, so thatās what Iāve been going with. They empty out a container of dirt/dust in about a half a day. Simple is good.