So sorry your poor duck is injured. The good news is, this is not necessarily as bad as it might look. If you haven't already (because I see this was posted several hours ago), take the bird in and clean the injured area thoroughly. As you noted the bird is shocky, you want to treat for that by providing a quiet, warm, comfortable place for the bird -- a box, crate, etc. Monitor food and water intake and waste output - monitor the wounds for signs of infection.
How is your duck doing? I had responded to you in the introductions section, but thought I would follow up with you here and see how things were going?
My dog attacked one of my muscovy drakes monday night too
. I took him inside immediately for a bath so I could assess his injuries, which were scary but not so bad. I cleaned them really good with peroxide and then betadine and packed them with triple antibiotic ointment. I put him back with the flock but after not moving much for two days I put him in pen in the shed where he can see and hear his flock but can rest. On Tuesday I had gotten some blu-kote and sprayed that on and it has worked really well. I reapplied it last night but my guy isn't eating, drinking or moving much. I syringe fed him some water and nutri-drench. I think tonight I'm going to stop and get some wet cat food and baby food and give him that and some egg yolk. I don't know what else to do for my poor guy.
How is your duck doing? I'd be curious to know if you've tried anything else that I haven't. Best of luck for a speedy recovery!