Best method to control the weed is pulling it by hand BEFORE it goes to seed. Once it's at seed, it's prolific. Best of luck to you. The reason your chickens won't eat it, is because it too, is toxic. Not going to mention herbicides that can kill it, as Big-Chem says they're safe, and well... they've been known to say whatever they want to make a buck. How many years did Big-Chem say roundup was perfectly safe when they knew for a fact that it was not? I don't want to debate that subject, just throwing the question out there as food for thought.