If you are making a dust bath you would want to mix it with sand. I always dust the floor of my coop and the new bedding whenever I change the bedding and in the nests too. There is a recipe around here somewhere for whitewash for painting inside the coop especially the roosts.
I don't know about the cats but I don't see whynot however I don't know the dosage I free choice it with my horses and I mix into my laymash to control insects...any deworming that happens with my layers is just a bonus. I truly love DE...wonderful stuff just be careful not to dust it onto your flowering plants as it will harm bees.
