Mr.Universe
Chirping
my first thing i would do is knock on unknown neighbors door and ask if hes lost chickens. this seems to be a area/zone epidemic as the other neighbor has lost birds as well. you can call the department of agriculture to have them come and do an airborne test and test the ground in unknown neighbors yard because of the epidemic. means all birds in a huge area are sick which is cause for concearn as that means this could be up to 1k miles or more are affected due to this