The chickens want revenge! You don't think much about chickens. For centuries we have oppressed them, grilling, roasting, stewing, and stuffing them in buns. We should have known they wouldn't put up with that forever. There would be revenge.
Now is that time. In the original, we had to send our best pilot to fight off the deep space chickens from invading Earth. They came out of nowhere, with no prior warning. They had superior numbers. It was only you who managed to repel the invasion and save humanity from a fate worse than grilling.