My neighbor adopted 4 full grown ugly yardbirds. He kept them in the pen for almost 2 weeks then let them out. They never returned to his pen from that night on. They sleep in the trees and are over at my house at sunrise. They wait at my coop until I let my chickens out to free range. At night they go back to the trees. The problem is biosecurity. They look healthy but what if they have diseases that could be passed on to my silkies?? And it's starting to get cold. Those poor bird roosting in the trees could freeze to death. And they are starting to get aggressive. When I feed MY chickens snacks they sometimes try to fight my chickens for the food! The neighbor really is a wonderful person and he doesn't know what to do. They roost too far up in the trees to capture them and put them back in his pen. He keeps his pen open with food in it but they will not go into it. First thing every morning they're at my coop. When they started to get aggressive I got my hose out and tried to spray them away but they just come right back. A fence between the properties is out because its over 600 feet and they'd just fly over anyway. I don't want to adopt them because they are aggressive and ugly. Besides, they wouldn't go in my coop at night anyway. The guy he got them from said they used to sleep in the trees at his house. Other than hoping an owl will carry them off, guess I'm clueless..and no I will not pick'em off with a gun while they sleep up in the trees!! Oh the agony!!!! Any suggestions?