I would recommend that you remove all bedding from the house and spray thoroughly with Poultry Shield. You need to use a pump spray and ensure that you get into all the nooks and crannies. When thia has dried, sprinkle a good layer of diatom on the floor, nest boxes and perch holders. Replace the bedding and let the hens back in. 3/4 days later re-spray the house (you do not need to remove the bedding) and again at the end of the week. Continue spraying once a week and replenishing the diatom when you clean out until you have resolved the problem. You will learn where the red mite harbour as the poultry shield will go a yellowy/green colour when you spray the mite. Have a look in our online store at www.poultryproducts.co.uk for these and many other suitable products.