The USDA keeps track of all sorts of agricultural statistics.
They seem to think that the US annual production of broiler chickens is ~9.1 Billion, with ~380 million laying hens in any given month.
If some nefarious adversary is going around trying to destroy the poultry industry, they seriously need to step up their game. At this rate it would take 38 years just to kill all of the egg layers, and someone would probably notice.
Thank you for the additional data!