I don't know if this is true but I have heard it repeated many times. It seems that a UK aircraft company secured the drawings for the chicken gun used by Boeing. They built the gun to spec and used it to hurl a deceased chicken into the windshield (windscreen) of a new aircraft under test.
The gun was pressurized to spec and the chicken was hurled at the windshield. It not only penetrated the glass but it kept on going and totally deformed the rear wall of the flight deck.
The UK aircraft company asked Boeing what went wrong. After a lengthy conversation back and forth it was discovered that the UK types didn't thaw the chicken prior to placing it in the barrel of the gun.
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The Cat