Sorry, I guess I was supposed to post introduction, but instead I jumped right in with my duck problem. I live in New Braunfels, TX on 6 acres. We have tried to raise chickens and ducks, but can't seem to keep them safe! Didn't expect an attack on my last duck during the day. I went to put him up for the evening and found him laying on the side of the pond with part of his upper beak gone. We do have hawks and coyotes so I'm not sure which would have been able to take off part of his beak. Can a duck survive with a part of the upper beak gone? Is there anything I can do to help him survive?
In answer to your question, yes, your duck can survive with half the upper bill gone, but you will have to make suitable arrangement for him to eat.
I had a rescued pekin that had been abandoned at a vet's office after being attacked by a raccoon when it was a little fluffy Easter Duckling. He did very will for 3 years and died from unconnected medical condition. I currently have a rehomed domestic muscovy that tore its beanie being aggressive. I replaced it anatomically the first time but he repeated the behavior while his bill was splinted, so he has had to live with his deformed bill since then. He manages without and extra provisions [and he's still quite aggressive!!]
Your duck will need a deep tub for feeding, as he is going to shovel up the food and scatter food everywhere. I hand fed treats to my pekin using a long tapering plastic tumbler. That way the scattered treats were contained in the tumbler and fell back down for him to eat. I would hand feed you duck until it has recovered. She will need extra protein while healing and extra vitamins [for example Rooster Booster poultry cell] in the drinking water. Then slowly get her used to eating out of a deep bowl. topping her up by hand if she isn't getting enough down at first.
You haven't asked how to protect you ducks and chickens. Your flock needs to be in a secure run with the top covered. Secure from predators means hardware cloth buried around the perimeter to stop a predator digging in. Hardware cloth from the ground for three feet up the sides to stop raccoons reaching in and grabbing -- raccoons can work in family groups with some on one side of a run scaring the ducks to run to the other side where another raccoon grabs a duck through the fence or bars. The top of the run needs more than a net that would keep out a hawk but not a raccoon. I would use strong chicken wire firmly fixed to the sides.
I have my ducks free ranging in my back garden, but its well shaded by trees and shrubbery. No hawk is going to take a muscovy drake and I doubt we will get an eagle in a suburban back yard. You will get eagles on 6 acres open land in Texas. If you want your flock to free range during the day you are going to have to have a dog or dogs that are trained not to go for the birds, but will chase away predators. I have had both raccoons and foxes in my suburban back yard before I had dogs. The dogs -- a beagle and a beagle foxhound mix -- leave the ducks alone but bark and chase rats, squirrels, raccoons and foxes. The foxes haven't been back and a raccoon and kits got no further than the fence and didn't return. I am sure the predators can smell the dogs and don't come even if the dogs are not out there.
Your duck also needs ducky companions, so please get 2 or 3 more and protect them all from predators! Please keep us informed on progress with the injured duck