Feathers and duck down filling, which provides warmth, resilience and excellent value for money. However, this is the heaviest of all down as the feather and down of a duck is smaller than that of a goose. A larger amount of filling is therefore required to make the duvet as thermally efficient as goose down duvets.
Duck down fill power ratings within the outdoor industry generally range between 500 and 700 fill power. Fill power is defined by the amount of loft that is gained under loft test conditions. The higher the fill power number the greater the loft and the greater the performance of the down insulation.