I posted this in another section, but no responses. Hoping someone will know?? "My chickens have figured out how to clear the fence and get out into the big yard. Which is fine, because we have a big place and they always come back. BUT, the problem is that we are constantly battling poison ivy and oak around our place. If I spray the Ortho spray on the poison ivy and oak in the evening after they are locked up, will it harm them the next morning when they are out and pecking at the ground for bugs? Everyone but my oldest is allergic to the stuff, and I actually have it now, so I really want to kill the nasty mess! "