I agree with
@DiYMama540
I have my chickens free-range in my backyard/garden area. There are some toxic plants to chickens there. Tomato plants, Deadly nightshade growing in fence line from adjacent property, Poke weed, Holly, and other weeds I'm not sure of. My chickens just don't snack on any of these. They graze in the lawn, as well as other plants that are OK for them.
If chickens have a choice of greens, they pick those that are not toxic for them.
I have read many posts of chickens getting sick or worse

from eating wrong plants. In MOST of these cases (that I read/responded), it was a plant that was growing into run area thru the fence/netting, and
run was barren/void of other greens. Common logic says,,,,,,, if that is the
only green item available,,,, chickens will snack on it.
WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
