Sorry to hear about your duck.
I'll first start off by saying, I do NOT like Blue-Kote, I'm not really sure of its effectiveness with wounds, I've never heard a vet recommend it, but it stains the feathers bad, and dye's the wound so its hard to tell what's really going on.
Examine her whole body for any wounds, if you see one, trim the feathers around the wounded area, about a 2/3cm circumferential zone will work, after that lavage the wound with either saline, chlorhexidine (Hibiclens), or diluted betadine. You can use a dish soap bottle to lavage or a 35/65 syringe. Then you can either slather the wound with a triple antibiotic ointment, I prefer Prep H since it increases the respiratory component in the epithelium thus promoting wound healing, you could also use a poultry wound spray like Vetericyn.
Just to reconfirm, she should be in a warm (80F-ish) area, away from flies, that's dimly lit, and stressful free. Some Gatorade, Pedialyte, or a poultry vitamin would be great to add to her water for a little boost.
A few questions, how long has she not been eating, birds need to eat, if she doesn't start eating soon she'll need to be tube-fed. Most birds with bite wounds require antibiotics, do you have any on hand, if so what?
