Does trying to live healthy make sense considering an imminent bird flu outbreak?

[Angrboda]

Where exactly do you think that I used argument from incredulity? And why exactly is it fallacious? I mean, if something is difficult to imagine, it is certainly less likely to be true, even though it can be true. Saying "I cannot imagine how F could be true, therefore F must be false." is arguably fallacious, but saying it is unlikely to be true is not fallacious.

The fallacy lies in your claiming it is unlikely to be true because it violates common sense. Common sense is just another name for an innate judgement about credibility. That's why "appeal to common sense" is another form of the fallacy. And no, not being able to imagine something doesn't affect the odds of its likelihood.