With chickens i noticed a kind of thoughtless greediness. Give them a patch of grass and some time - they will eat that down to bare earth. They're not thinking 'maybe we should conserve some of that for later'. The impulse to consume is overpowering - even when it will result in their own doom.

I've noticed that whenever there's a threatening natural event like a major earthquake that knocks out electricity, a serious typhoon, etc., I want to eat. It's a weird sensation and even though I'm acutely aware of why I feel it, it doesn't matter. The awareness of wanting to eat as a natural response to the situation is not enough to quell the urge entirely.

But we've gone way beyond that, as you point out. Our very economy depends on consuming more than we need, or even want. Advertising exists to make us want products and services that we didn't want before being exposed to the advertisement. And they're very good at it.