Q: Have chickens tried to destroy a Space Burger before
A: They have. But Space Burger Corp. has over 7 billion stores, so a few thousand destroyed stores is not going to make a significant impact.
So my idea is, chickens try to destroy space burger that no recruit is orbited with and no stores in the star system. This event can take a day, the next day, the space burger will be gone, it will instead be replaced with a couple of droids, the next day, the space burger will return, but food gives less keys for a limited amount of time.
While chickens fill the store, space burger droids will disappear or be replaced by common security droids.
Recruits can save the space burger by flying to it during the chicken raid and fly a long chicken invasion mission.
If a recruit won, the space burger will be saved and offer more keys for food.
Hard chickens flying around the store means that the mission will be hard (higher key bonus), easier chickens flying around means that the mission is easy (though, key bonus for food will be litttle)