Maybe the disciples told the reincarnation story the opposite way. Humans should be at the bottom of the ten worlds, and you progress up to poultry when you are enlightened enough to realize how fleeting life is. And you give your life to those of lower understanding than you so they have a living chance. So every time you partake a meal, whatever your struggle, remember someone who was there before you, saw it to the other side of the tunnel and decide to give himself to you so you can live another day.