The FAA has a device for testing the strength of windshields on airplanes. They point this thing at the windshield of the aircraft and shoot a dead chicken at about the speed the aircraft normally flies at it. If the windshield doesn't break, it's likely to survive a real collision with a bird during flight.

The British had recently built a new locomotive that could pull a train faster than any before it. They were not sure that its windshield was strong enough so they borrowed the testing device from the FAA, reset it to approximate the maximum speed of the locomotive, loaded in the dead chicken, and fired. The bird went through the windshield, broke the engineer's chair, and made a major dent in the back wall of the engine cab.

They were quite surprised with this result, so they asked the FAA to check the test to see if everything was done correctly. The FAA checked everything and suggested that they might want to repeat the test using a thawed chicken.