When I was researching safe vs toxic plants Cilantro and Parsley were no-no's. Anyone have any input since chickens will eat just about anything including toxic plants - i.e. tomato vines and leaves are no-no's but some will stupidly indulge anyway.
Mine LOVE Yellow Woodsorrel and its good for them. Its often eaten as a salad green by people and its high in vitamin C. It grows in most yards as a weed in the Southern half of the US.
This stuff, especially when its fruiting:
Fruits look like this and taste a little like sweet and sour candies: