Fallacy?

I'd just add that most animals when they die in the wild die in agony, some may even start to get eaten while they're still alive. 

Well the first premise is just like " if lion eats poop then it's okay to eat poop

Right, the first premise is a poor claim with no support.

Yeah

The appeal to normality is pretty close... if people are doing it, it must be right. This could be extended to "if it is normal for animals to do it, then it must be good/right."

Now that you mention it, if I heard someone say "appeal to normality" I would think that he is using the degree of how common something is to determine goodness. Coincidentally a couple of days back, there was another thread where someone asked about the "It's not bad if it happens to everybody" and I replied that I would name it "appeal to normality" if I gave the names to fallacies, but the definition of "appeal to normality" uses normality in the context of "social norms", not something normal/common between members of a group(as it is here where we talk about the group of animals, including us humans). Why should we use "normality" in the title of the fallacy and then limit it to social norms and not something normal/common in general? Why not "appeal to normality" for something normal/common AND then add a subcategory "appeal to social norm" specifically for social norms? Doesn't that make sense? Isn't that more intuitive and less misleading?

That is why I said it is pretty close, not and ideal match. As you point out, social norms of animals don't transfer well to social norms of humans :) If we ignore the species issue and see the behavior as simply the majority group (and humans are the subgroup) then it is pretty close.

Perhaps there should be an "appeal to commonality." I want to do a little research into fallacies that lead to a "good/bad" conclusion rather than a "true/false" conclusion. Off hand, I get the sense that when we start concluding that something is better or worse, fallaciously, we are entering the realm of cognitive biases. Of course, there is much crossover. Just thinking out loud here :)

Well there's already a precedent with "good/bad" conclusions. That is cherry picking or appeal to novelty or appeal to the law . These are all conclusions of better/worse decisions = subjective evaluations. What is good for me may be considered bad according to someone else's criteria. So as long as we consider the same criteria I don't think it is fallaciously to conclude that something is better or worse nor that we have cognitive biases. The fallacy is to insist that others accept your conclusion even though they may have different criteria as to what they consider to be better. 
"appeal to commonality" would clash with "appeal to normality" in that you cannot intuitively distinguish between them. "appeal to commonality/normality" and "appeal to social norms" clearly distinguishes the two without bringing any confusion. Of course I do get that "appeal to normality" is already established, so the question is "Is there a way to change the established name of a fallacy to something more meaningful"? We had the same discussion when I asked you about the subverted support , where I guess nobody alive could ever imagine what that is, just by the name of it, and I remember you agreed but you also told me then that if it was up to you, you would rename half of them :)
So I do get it, but it's a shame though, to continue to use misleading or completely incomprehensive names because of tradition really. How about using your book and your audience to form a core of people that use intuitive, non-misleading names instead? And little by little reverse what is established. For example the "unfalsifiability" is the title and then the subtitle is "untestability", but "untestability" is far clearer than "unfalsifiability" and in the definition the "cannot possibly contradicted" creates confusion because it applies not only to "untestable" claims but also for "true/valid" claims (which since they are true, they also cannot be contradicted by any observation or experiment). So how about starting with "unfalsifiability/untestability" and then move on to "untestability" aka"unfalsifiability" in the subtitle (in the "also known as" section)? Or something like "appeal to social norms" (formerly known as "appeal to normality") instead of just "appeal to normality" and at the same time insert it as a different fallacy under the name "appeal to commonality" aka "appeal to normality" and then reverse it as "appeal to normality" aka "appeal to commonality".
Just thinking out loud here myself :)