I don’t see why elector PSP wouldn’t work for the mites around the coop - I would definitely give that a try. Careful with Ivermectin if you have a dog around that might eat chicken poops. There is a mutation common in a number of breeds (collie dogs for example) MDR1 that keeps the dogs from properly metabolizing the drug and it can make them very sick and kill them. Ivermectin gets excreted in the droppings and stays dangerous to those dogs for a long time.