CHICKEN ANATOMY 101
The cape-also called the "neck" covers the neck, as well as the top and back of the head, of the chicken. A cape contains feathers of many different sizes; the smallest are found around the comb. A dry-fly cape comes from a rooster; a soft-hackle cape comes from a hen.
The saddle-hackle "patch" is actually just the skin on the rooster's back, although the feathers drape to either side. Depending on the species of rooster, saddle feathers are useful for making everything from fine dry-fly hackles to long, webby wings and tails for large saltwater flies and bass bugs.
The name "schlappen" comes from the German verb that means "to dangle or hang loosely," and it is a good definition of these feathers, which are located between the saddle patch and the tail. The large feathers are used primarily for tails and wings on saltwater flies and streamers. Schlappen is most commonly found strung in individual packages.
When a rooster "puffs-up" as a show of aggression, he offers a good view of the breast pelt. The soft, rounded feathers that cover the chicken's breast are used for forming the wings on Matukas and the throats on hair-wing Atlantic salmon flies.
The humerus is the upper bone of a chicken's wing. The feathers that cover this bone have very stiff barbs and are sold as tailing material for dry flies.
There's no common name for the nether part of the chicken below the breast, so the prosaic "butt" will have to do. The feathers from between the legs are very soft-some are even softer than turkey marabou-so they add lifelike action to nymphs and wet flies. You'll find these pelts in fly shops under the names Chickabou offered by Whiting Farms) or Body Marabou Patch (Ewing Feather Birds).