Crazy Sheep and weird reactions too...?

I use to live on a farm and we had about 30 sheep there was this one sheep that I use to feed black licorice and when I did she would go crazy! She would start shaking her head back and forth really fast running around and running into the other sheep slamming her head into there sides. Why is this? is black licorice a narcotic to sheep? It did not kill her and she only acted this way for about 5 minutes then she was back to normal.