hi there i had the same problem but not that bad i used a powder form in the nest and its called pestene which costs 15 dollars nz thou but be cheaper everywhere else lol, which pestene is a insect powder and it kills mites and lices and its safe with the eggs as i use it everyday for my girls as i place the pestene in there nest in a heavy dose which work as they lay in the nest while laying there eggs the mites and lice leave the chicken and go straight for the pestene which destroys the mites and lice straight away and i dose under there wings and bum just to be safe but thats just me, as i have 21 different rare breeds so i have to keep my girls in perfect condition and butter is also good and i have also tryed butter and it kills the mite as they need air to live, i apply butter just before there bedtime all over there legs in a heavy dose which i rub all over there legs the butter stays cold and detroys the mite faster cheap and works great but every1 has there different ways of destroying the mites,