Ok, I have done a bit of looking and can not find a solid answer. This is something I have always wondered. If is possible that wild waterfowl and birds can spread illness to your backyard flock of chickens and or ducks, geeses etc...? If so what are some of the illness that wild birds carry? If it is possible, and since alot of it is air-born how do commercial/large backyard places deal with the change of sickness. Thanks.