Removing dog urine from a feather duvet is a difficult task. There are two issues to consider: removing the urine stain and removing the smell. Feathers are a natural material. They will hold odors and they can be damaged by improper cleaning. The trick is to remove the stain and the odor while keeping the feathers and the loft intact.
Remove as much of the urine as possible by blotting it up with a towel. Apply pressure until no more urine appears on the towel.
Fill a bathtub with room temperature water. As the tub is filling add the correct amount of laundry detergent for a small load as indicated on the cap. Also add 1/4 cup of baking soda. Mix until dissolved.
Place the duvet in the tub and gently squeeze the water through the duvet. Pay special attention to the location of the dog urine stain.
Empty the bathtub and refill with cool water. Rinse the duvet until no more soap appears and the water runs clear. This step will need to be repeated several times.
Gently squeeze as much water as possible out of the duvet. Do not wring or twist. Place the duvet in a clothes dryer set to air only. Also put several clean tennis balls in the dryer to prevent the feathers in the duvet from clumping. If a clothes dryer is not available, then hang on a line to dry, fluffing the duvet every half hour to prevent clumping of the feathers.
Set washing machine to the largest load size. Select warm wash, cold rinse, and delicate cycle. Set agitation setting to low.
Add laundry detergent as indicated for a small load. Add 1/4 cup baking soda as the machine is filling. Add the duvet.
Check the duvet after the wash cycle completes for any signs of staining. If a stain exists, repeat the wash cycle another time.
Set dryer to air only cycle. Add tennis balls and duvet to dryer. Dry until the duvet is completely dry.