Most plants that are labeled toxic are more like just not tasty. Most animals will not eat poisonous plants because of the taste. Very few plants actually kill. I can think of a few, but most will just make you sick for a while. I would Google the tree and check what it is that the tree or berry does. You will be better at finding info if you look for the trees botanical name. What you are calling it is just a common name, and it will very around the country and the world. Botanical names never change. It's still good to remember that chickens are walking garbage cans, and will eat just about anything whether it is good for them or not.
