I saw a few of the feathers that were washed that way. They looked normal.
I can't ask them about detergent, cycle, or temperature until we visit them again, unfortunately.
I have a friend that would put wet(plucked) Feathers in a pillowcase, & wash them in the washer, then dry them in the dryer. They say it works well.
Me I just use a bag & hair dryer.