Why do you have to give feathers a good shake on winter time?

In winter, feathers can become clumped or matted due to moisture, which can inhibit their insulating properties. Giving feathers a good shake helps to fluff them up, allowing trapped air to circulate more effectively and enhance insulation against the cold. This process also helps remove any debris or moisture that may have accumulated, ensuring that the feathers maintain their warmth and buoyancy.