Call me silly, but here's my explanation;
There have been lots of crazy weather patterns lately which have created unusual storms and such. I'm thinking a large flock of birds could get caught in a major updraft lifting them to as high as 50,000 feet and they could have been asphixiated and then plunged back to the ground causing the trauma to the bird's bodies that they saw when examining the dead birds.
I think the answer is much simpler than people are making it out to be, but what do I know.
