I made a duck and barley soup a few days ago, because I had a duck carcass to make broth with. I stripped the meat from the carcass, then boiled the bones and skin up with the lemons from the cavity when roasting, a couple of bay leaves, and a shallot.
I pretty much sauteed onion, garlic, carrots (finely diced), mushrooms (halved and quartered), a sprig of rosemary, one dried arbol pepper, and a few peppercorns in duck fat, then put about 0.5 c pearl barley in and stirred until all the fat was absorbed, added a cup-ish of dry reisling (whatever was left in the bottle) and when that was evaporated added about 2 L of duck broth... to a boil then reduce to a simmer... when the barley was cooked and the soup looked done, I put the reserved duck meat in and heated through.