What type of duck is he? You might want to use an eye antibiotic if his eye is infected that infection can travel to a weak part of his body and then a bad bacterial infection will start to brew. The one that has done well is BNP.(Vet gave it to me) It is a combo of Neomycin, Polymyxin B Sulfates and Bacitracin. Make sure it's for ophthalmic use. I'm sure you can find it at a feed store. If they have Baytril. That's good for bacterial infections especially in birds.(It's oral) Always good to keep on hand.
If you can take your turkey to a vet....one that treats birds, you can at least get an idea of the best med to put him on and the Dr. might give you some recommendations. Some vets are friends with other vet clinics and call each other and research if they don't know or specialize in that particular animal. Mine does.
Did your duck get attacked too?
Oh yeah "Rooster Booster" was recommended to me for my duck as well as my chickens. It's electrolytes and vitamins. And it works well for me to get my guys going again.
They say when a bird starts to show signs of sickness....they are VERY sick and if you don't jump on it right away, you might loose them.
This is just my experience and I am sure there are people on here that are wise beyond my years with these types of things.
Good Luck!
Your poor guy.(poor duck too) I'm sorry. I hope all goes well.