I have had the hardest time with an extremely invasive plant in my yard, I dug up the whole root system this past spring and it still pops up everywhere. Trumpet Vine or trumpet flower is poisonous, and itchy, for all animals and humans, and yes my chickens. The original plant is in my neighbors yard, so I cant kill their plant but have been battling it in my garden and yard all summer in fear that my little dinosaurs will get a hold of it. But they really show zero interest in it which makes me happy. I've also been learning the hard way as this is my first flock, not quite old enough to lay eggs yet even, that they sample everything and pull the roots up on all the plants regardless if they eat them and really like the garden and the plants trying to I'm trying to grow or get to maturity from them. I've pretty much called this summer garden done and have been setting up chicken wire rings around all my fall garden plants. Here's what a trumpet Vine looks like for those who don't know.