Ok so my comments about using frogs in war yesterday were in jest but it occurred to me there is a potentially interesting question in there. Something along the lines of...
In a medieval setting you have a band of rebels hiding in the (forest/swamp/mountains) where (bird/rodent/reptile species) is abundant. How could the out armored and out weaponed rebels utilize these creatures in a battle to even the odds?
@Green @ArtOfCode Thoughts?
Oh screw it I am asking it anyway, chat is too quiet today!
I should have made one thing different though: Immortals will only recover from injuries that would kill them. That would make the question different and more like what I had originally imagined.
It would also be an obnoxious change that would invalidate many answers, so I think that's an edit I'll toss in the "Bad Ideas" bin.
Your herbivores question is doing very well. Kudos to you!