Where I live Ivy is horribly invasive and can destroy trees and cause major damage to buildings. I'd recommend grapes, on a trellis which may block his view. Grape leaves are great nutrition for the Chickens as long as they are getting at least an hour of sunlight a day - and they go crazy for grapes and raisins. We have 2 kinds of seedless rapes shading porches. I assume seeded grapes would make your eggs high in Omega 3's. They can be grown from cuttings, and like to be curt back often, so they make great Chickie fodder.I think these might be poisonous to chickens...? I surely don't want your cure to cause another problem! Although chickens have a pretty good innate knowledge of what they should/shouldn't eat.
My chicks moved outside at 6 weeks. There was an iris leaf near enough to peck. One bird pecked it one time. Somehow, they usually know.
I am so sorry this is happening to begin with. This neighbor has such a tiny heart, I'm surprised he's even alive.