The black birds fell from the sky over a 1-mile area.
The Arkansas Game and Fish Commission said the birds did show signs of physical trauma. Officials said the birds may have been hit by lightning or high-altitude hail.
Some of the dead birds will be sent to a lab for testing.
Commission ornithologist Karen Rowe said that similar events have occurred elsewhere and that test results "usually were inconclusive." She said she doubted the birds were poisoned.
The Associated Press contributed to this report.