Scientists at Rolls Royce built a gun specifically to launch dead
chickens at the windshields of airliners and military jets all
travelling at maximum velocity. The idea was to simulate the
frequent incidents of collisions with airborne fowl to test the
strength of the windshields.

American engineers heard about the gun and were eager to test it on
the windshields of their new high speed trains. Arrangements were
made, and a gun was sent to the American engineers.

When the gun was fired, the engineers stood shocked as the chicken
hurled out of the barrel, crashed into the shatterproof shield,
smashed it to smithereens, blasted through the control console,
snapped the engineer's back-rest in two and embedded itself in the
back wall of the cabin like an arrow shot from a bow..

The horrified engineers sent Rolls Royce the disastrous results of the
experiment, along with the designs of the windshield and begged the
British scientists for suggestions.

Rolls Royce responded with a one-line memo:

Defrost the chicken..