I built a covered area in my chickens' pen so that they'd have some bare ground during the winter, and Last year I put down some traction sand to give them a dust bathing area since the ground freezes hard. I picked up another bag of traction sand this winter, but I noticed that it says this on the bag: "Warning. Avoid breathing dust. Contains crystalline silica." I don't know if the sand I used last year had this warning, if it did I didn't notice it. It doesn't sound like this sand would be good for them to dust bathe in, since there's a warning not to breath it. Does anyone know if this sand has added stuff that might make it dangerous?