Extending the duration of the empty period is not an effective way to reduce red mite infestation. Red mites are extremely robust ectoparasites and can for example survive submerging in water for over 10 hours. But more importantly, they can last for at least 9 months without feeding. So solely leaving the hen house empty for a few additional weeks during the turnaround period will not be effective at all. Thorough cleaning (including wet cleaning with water and soap) and disinfection are paramount to effectively reduce the red mite population in between flocks. In addition to this, complementary approaches can be used during the empty period such as heat treatment (only if the housing system and equipment can withstand high temperatures) or the application of silica after disinfection about 1-2 days prior to the placement of the new flock. By applying such methods, you should hopefully be able to keep the mite infestation under control for a longer time into the duration of the flock.