Hello, We seem to have a lice problem as it is cold and wet here and the chickens have not been using their dust bath that we built for them! We have cleaned the coup and dusted but the coup and chickens in DE but it hasn't seemed to work. I bought some 0.35% harkers ivermectin and used it on Saturday but some of the chickens have a few stragglers! Does anyone know if it is okay to treat them a second time after a week of first application? I want the pests gone. Chickens don't seem bothered or irritated at all, but I feel awful for them. Thanks in advance.