by low donkey brain, do you mean 0% or 100% donkey mind?
Low meaning less; the donkey behaviors boost a number that I generally refer to as donkey brain; when that number reaches certain thresholds, that's what triggers the different texts, behaviors, and endings. To start this specific scene, you want to go to the Edge of the Farm basically right after running from Faye in the farmhouse, then wait in the Crossing the Wheat scene for the event there to start.