Hi and welcome to BYC! I know some folks mix DE in with their dirt for the chickens to dustbathe in. I think if we didn't have plenty of dirt for my chickens to bathe in, I'd buy a large bag of plain potting soil.
Do you have a fireplace? If so, when it gets nice and cold this fall, just throw a log on the fire, let it burn down to ashes, then sweep the cooled ashes into a pan. Voila, wood ash. You could also do the same outside by fashioning a fire pit. Just use real wood, not those fake fireplace logs.
Mine just use dirt. They're always digging under the shade of my shrubs, where the ground is soft. they'll dig right down through the mulch.
