Hurt like splinters and such from wood chips? Darn, I thought wood chips would be an awesome thing for chickens to peck around in. We can usually get them for free, too.
Caliche isn't always in one thick slab layer, like a house foundation. It can concentrate into large lumps. Easy for squirrels to burrow around. We will free feed our hens and we don't want to feed the squirrel population, too. They're a
huge problem here. I suspect they've tunneled under the house, too, but that's for the homeowner to deal with.