I learned a terrible lesson today. I cut a mealy apple in half this morning and put it out for the girls. I didn't even think about the seeds as I watched one of my girls promptly eat all of the seeds first before starting on the apple. I just came back from an errand and that same hen is now lying dead on the ground. She was fine and healthy this morning and now she's dead. I feel just awful. I have always heard that apple seeds are poisonous, but never worried about it because I've heard you would have to chew up the seeds of several apples to be poisoned. My girls regularly eat all the leaves off my rhubarb when they can get at it so I know their systems aren't sensitive to the same things we are, but apparently apple seeds are death on chickens.