I wash my down pillows in our fromt loader on a woolen cycle. I put just a half amount of soap in the dispenser and add some fabric softerner to the soap. I figure that it is important not to strip the oils out of down. Just a tiny bit of softener to rhe rinse. Then I use the extra hig speed for all spins. That dries the doun some and then just toss them into the dryer on low. Pillows come out wery puffed up and springy. A few pieces of down leak through the fabric but I just wipe it off. Often takes a very long drying time. After the auto dry stops I set the machine to timed dry and go for another half hour or 45 minutes to be sure. If your fromt loader is large enough the duvet fillet should fit there too, but I have never tried that.

Bass Pro Shops carry a Down wash I use on my comforters and it does not remove the loft. I follow the directions on the bottle but only use 1/2 dose in a front load machine. You have to be careful with what you use when washing down/feather items or you will remove the natural loft.

I think Martha Stewart has how to clean down on her website.