Yesterday, I gave them some black bread as a feed supplement. They eyed it cautiously, circling with suspicion. Normally, they dig in to the white or whole wheat bread, but this was obviously different. It must be a trick... someone was trying to poison them or something. The pumpernickle bread just sat there for the whole day, untouched by guinea beaks. I finally gave it to the chickens, who scarfed it down quickly.