So i'm making some duck soup with a carcass that i just butchered. I see a lot of recipes that call for a roasted chicken carcass and I'm wondering if i should just boil it uncooked for the stock, and will there be a difference?
All depends what you're going for. The french method would be to slightly oil (if dry bones, but if fatty carcass like duck, no prep necessary), then roasting in the oven. Then you simmer for hours. This is with aeromatics and other flavorants, by the way.
Asian way is to just boil the shit out of it on a low, rolling boil for hours. If you want a clearer broth, you put them in water until it boils, dump them in the sink, get all the brown parts off, then make the stock.
(skim and strain both, which I probably shouldn't have to mention)