Suddenly: chicken queen!

I know that anger increases more for each burrow kill if you kill the burrows fast.
I think it has to do with player aggression rating.
When you had 3 player aggression rating each burrow kill seemed to give you 3% anger.
Although when you had like 4 aggression rating it seemed to give like 10% anger, then 20% and then 50%.

Killing burrows steadily throughout the game and keeping Player Aggression Rating between 1 and 3 is usually the easisest way to beat chickens in my experience.

Fixed for stable

In the meantime, reduce burrow queen time in modoptions to something like 15 seconds when playing Custom.