happy duck
Crazy duck mom
Do they free range? She could have gotten into something. How often is she limping? Check the bottom of her feet for bumble foot. Looks like she must egg binding. You can put her in a tub of warm Epsom salt water(don't let her drink it!). I would give her some electrolytes and niacin, maybe some probiotic powder. Take her away from flock so she does not spread to the rest of flock, if it is something that can spread. Has she had or seen anything terrible happen like a friend dying or something of the like? Keep us updated. Following.