The signs that turn this into a phone call rather than a look: gaping or stretching the neck repeatedly, a foul smell from the mouth, swelling in the neck or throat, dropping food or struggling to swallow, not eating or drinking.
And one that is urgent rather than concerning. A goose with weakness and a limp or floppy neck needs a vet now. Some toxins produce exactly that in waterfowl and it does not wait. Separate her from the others either way while you work it out.