Hi all. I have six hens. Their coop is the red Lancaster that is within a 20x18 run. I also have a small rabbit hutch within the run that my hens have access to. I have a cat litter box in the rabbit hutch filled with sand, ash, and DE. Also in the run I have a covered cat litter box filled with the same dust bath mixture. They won't use them. I check every day to see if they used them to dust bath in and it seems they are not. Any suggestions. Thank you.