Down is the soft undercoating of waterfowl, which is comprised of individual down fibers that are connected to one another at a central point.

Nestling Down

Underdeveloped down made up of soft fluffy barbs radiating from a sheath, is called Nestling down. Nestling down does not have quills.


Plumage consisting of soft quills and barbs.

Down Cluster

A group of components including down, nestling down and plumules.

Species Identification

Feathers and down are tested to determine what species of bird they come from.

Fill Power

Fill power is a measure of loft, or the insulation ability of down products in cubic inches per ounce. The higher the number, the more fill power there is.

Oxygen Number

Oxygen number indicates product cleanliness. Down and feathers are soaked and agitated in a solution of pure water, which is then measured for organic material. The lower the number the better, the cleanest samples measure 1.6-3.2, the highest number allowed is 10.


Turbidity helps determine if dust or dirt (organic and inorganic) is present in the down and feather. A sample of down or feathers is soaked and agitated in pure water, the water is then measured for clarity. U.S. and European standards require a result of at least 300 mm. Very clean samples register at 550 mm or higher.

Thread Count

The thread count is the number of threads per square inch of fabric, measured at least five times and then the results are averaged together. Two-ply yarns are counted as one thread and may not be used to double thread count. Generally, the higher the thread count is, the more down-proof the fabric.