From my Texas Master Naturalist website:
“ Birds enjoy the fruit and help this plant reproduce by transporting the seeds. White tail deer, goats and cattle browse the leaves. However, for humans, the alkaloid compounds are bitter and can cause gastric distress. Carolina Snailseed is not considered fatal to humans, but its relative the Cnada Moonseed can be. Canda Moonseed is found much farther north.”
I looked it up because my chickens go crazy for them too.