One of the best, if not the best thing that I have used over the years storing large quantities of feathers, is go and get some cedar bedding like used for your dog beds. Put your feathers in what ever container you like and sprinkle liberal amounts of the begging in the container. Same principle that the elders used to do by putting their wool and things in cedar chest.
I also went and got a bottle of spray used to spray down bird cages for mites. Pump a few sprays of that in the container as well, and never lost any feathers.