I did a longer post on fluffing feathers a few years ago, but since I was doing it again the other day I thought I'd do another short one....I was happy to discover a big stash of black ostrich feather seconds I'd bought on one of the last big sales Ostriches Online had before they disappeared. Seconds often have "holes" in the feathers - places where the barbs are missing, and are generally not as full and fluffy but after some fiddling, curling and layering they can be quite nice.
First I ironed some of the feathers that had barbs pressed up against the shaft of the feather to make them fuller and steamed them with the iron to make them fluff up a bit. Then I steam ironed the feathers right side down, starting at the shaft and ironing towards the tip and curling the feather as I did to create a nice curve in the whole feather.
You can curls the barbs by taking a blunt scissor to them in much the same was as you do with ribbon to curl it. You will lose some of the barbs but this will make them look much fuller and fluffier. Then I stacked three feathers together, trying to match feathers with similar curves, and shaved the bottom off the stem of feather that goes on top, top and bottom off the middle and top off the bottom feather so they stack better. Then the stems can be hot glued or sewn together.
So from left to right: feather straight from the store, feather with curled fronds and stem, layer of 3 feathers with curled fronds and stems.
Be forewarned, this is a bit messy, you can end up with barbs, feather "dust" and bits of the shaft everywhere so do it over a trash can!