You'll have to clip it, because if you won't tube feed and she can't eat, she'll slowly starve to death. If you clip it and she still won't eat or drink, and you won't tube feed, you have to figure out a way to cull her or have someone else do it, because otherwise she'll slowly starve to death.
Depends on the situation. You don't need to tube feed her if she's eating and drinking on her own, but otherwise she'll just starve to death. So if you can get her to the point where she's eating and drinking, then you can stop. However, if you can't get her to that point, it may be better to...
Those are both oral antibiotics, I believe. Pretty sure you can get them without a vet. @Eggcessive and @Wyorp Rock certainly know more about this than I do.
https://www.backyardchickens.com/threads/step-by-step-tube-feeding-guide-pictures-under-construction.1064392/...
If she won't eat, there may be a crop issue going on. If there isn't and she still won't eat, you may have to tube feed her. I have no idea if she has a reproductive issue, to be honest. The antibiotics that are usually prescribed by BYC ers are Penicillin and Amoxicillin.
Is there a way you can separate her from the others to eat where she is still with them, like putting a dog crate in the run with her special food and a deep dish of water, then putting her in said dog crate?
Yes, but how long has this issue of her not being able to eat been going on? I would try offering her some wet, mashed up chicken food in a deep dish, and some scrambled egg. You have to correct the beak issue so that she can eat- I'm not an expert on it, but I believe that cornstarch helps stop...
You don't want to get antibiotics if you don't know what you're doing them for. How long has she been not getting food+water?? If she isn't eating, that would be why her keel bone is getting more and more pronounced.