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

[Spongebob]

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.

I don't know what the original argument was, but this is where you are falling short.  You seem to understand that making this statement (bold) is definitively is false, but then you waffle and say that it is "unlikely" to be true.  That is equally false.  Your ability to understand a concept or the overall complexity of a concept has zero impact on the truth of that concept.  It only informs the degree of evidence necessary to support said concept.

Let's consider something that is not complex at all, yet clearly difficult to accept as fact.  Consider a stone statue that reportedly bleeds from the eyes whenever Christians come to it in prayer over some misfortune.  This concept isn't difficult to understand at all, but it is certainly difficult to accept as factual because everyone knows stone does not bleed (not actual blood anyway).  This defies what we know to be a simple fact of nature; stone does not bleed.  And in this case it is likely to be false because it goes against a simple and commonly accepted fact of nature.  So in order to accept this as factual, we need considerable evidence.  I don't know, maybe you are conflating these two approaches to logic.