So i just found that my chickens have mites, i think it started with my broody, since all of the babies have them. Also the babies in the house (that were under her for a few hours, she rejected them) have them. I treated the whole flock with Ivermectin pour on and dusted with DE. I will be changing out their shavings tomorrow. Do i need to retreat with the ivermectin or will one treatment take care of it? Is there anything I am missing? Are there vitamins i should be giving them?