Have you ever heard of bumble foot? It doesn’t look too much like one except hard to tell by pics if the blk is scabs? If the swelling is coming from the foot it’s an infection also could be a niacin deficiency Pekins are especially prone to it and since many of us don’t have access to duckling specific feed have to supplement since chick feed doesn’t have enough for water fowl. It’s very important for healthy leg muscles, if in the US go to TSC and look for Durvet liquid b complex it maybe in the cattle section it will say injectable but we use it orally for our birds you can start her on it ASAP you maybe able to get her up an walking again but this deficiency can lead to death or crippled duck if not treated. Put 1 ml over a tasty treat so she gets full dose daily. Hopefully she’s eating and drinking? Can you wash her feet real good an post a few more of the bottom of her feet or did you already do this?
