It can be used as a wormer when added to feed at a rate of up to 15% into daily rations. If not being consumed in the feed then add to warm water to make it more of a gruel. Externally, add a handful of DE to their dust bath and in the chicken coop when it has its weekly clean out. Place under the litter to absorb moisture and odours. It will also help to create an insect barrier. When mites and lice crawl across the DE, their bodies become crazed and they dehydrate.