Furthermore, why would they leave the corpses? If they actually are infected you would never want to leave the corpse or have to come back for it later, and if

Furthermore, why would they leave the corpses? If they actually are infected you would never want to leave the corpse or have to come back for it later, and if they aren't, well, you have a super creepy blood-drained corpse with various organs surgically excised just sitting there on someone's property as a magnet for panic and conspiracy speculations. If the govt actually wanted to collect cattle for this kind of testing, they could easily pass a law that let them take animals and pay market rate for them. I imagine this would be much cheaper and simpler than ongoing covert helicopter operations combined with the cost of the investigations that the FBI did in the '70s. It's an explanation that makes basically no sense