My little flock of chooks are in need of some shade and I am considering planting a hops plant to vine up their pen fence. I just read today that hops are poisonous to dogs, etc., and that all parts of the plant other than the hops themselves are poisonous (to just humans or all animals I wasn't clear on). I am concerned that my hens could get at the leaves, etc., and eat them. Knowledge and advice please? Thanks!