So sorry to hear about your babies. Mine were attached two weeks ago by a mink. I lost 8 calls and two Appleyards. I was devastated! Still am. We caught the mink though, was hiding under the straw. Your pictures do look very similar to the injuries my ducks had. 13 survived with varying injuries. I took my Pekin Percy to the vet as she was definitely the worst of them. She was prescribed antibiotic and a liquid pain killer. Her neck looked bent and swollen which was due to the soft tissue damage from the bites.
I was really worried also about not drinking and eating. But I can tell you that after about 4 to 5 days of TLC, quiet, heat lamp, they really started to turn the corner. I did put pedialyte in their water and they would only eat peas and some corn, but it was better than nothing. I was ready to start tube feeding (thanks to casportpony excellent instructions) but it never came to that. Most of their wounds have scabbed over, but I still like to apply some polysporin on them. They are all eating well now thankfully.
Because of their neck wounds it took a while for them to be able preen properly so I turn my blow dryer on low and they Loved it! I would also put live mealworms in water and they would take that as well. I know what you're going through, it's heartbreaking to see them in any kind of pain. Sending best wishes for recovery.