I've read where some folks will sprinkle PDZ on the floor before adding bedding, when they begin a Deep Litter round, and will add more PDZ as they add more bedding. I have a 6-nest metal nesting box, I sprinkle some underneath the nest pads. Standlee adds it to their Flock Fresh bedding. If you decide to use it, be sure to get the bag with the horse on it, not the chicken - the chicken one is seriously overpriced!