Great article, hiwall!
Relative to the 9 billion chickens you mentioned: I have often thought that they are probably one of the better animals to have in a SHTF situation, IF you have feed. They could be raised in urban areas, but from all of my reading of rural Nebraska history in search of my family, stealing chickens was not uncommon during rough times. The next step would be to be able to butcher it, which most city folks could not do. Heck, I've even known some rural people who have never cleaned a bird.
Cleaning deer and such: anyone who has ever been involved in butchering a deer realizes it is not for someone who has never done it before.