I can back up that some chickens will give ZERO fucks about anything your unarmed ass can try to drive them off with. I tend to use flocks of chickens (think Legend of Zelda) to attack the players when they say they're getting bored of no combat.
The battle is usually started when they notice a chicken in their path. Any attempts to hurt the chicken or get within 10 feet of it makes combat immediately initiated with a surprise attack by a lookalike of my own rooster; silvery and black feathers with a tiny hint of blue tinting, flecked with gold. The rooster calls for your doom.
Killing the rooster is the only way to render the eternal flock docile, until that happens, more chickens will fly in every turn.