A timeline of the events would be ideal to map out events.

There was an earthquake in Ohio in June and Indiana Dec. 30 during 2010. These are rare.

One possible answer for the dead birds that I haven't heard, but have been posting is the open air burn or incineration of mustard and nerve gas agents at the Pine Bluff Chemical Weapons Arsenal 57 miles from Beebe.
The Army has been "cleaning up" for 2 years and just six weeks ago announced they were done. Except with other hazardous waste. It is possible that something went wrong or the Army wanted to test the chemicals on animals. We have seen animals in three states,but think about what we haven't found. Those birds landed in populous areas, not in nature.
There could be thousands of more dead animals out in nature w/o us knowing.

Food for thought

Grace be with you.