Stress test for an aircraft's jet engine (or other device designed to withstand the ingestion of high speed poultry).

Since striking a bird at the typical cruising speed of an airliner can cause significant problems for a jet engine, testing is done to see how well (or badly) the turbine blades can withstand an impact of this nature. Since it is easier to controllably launch a chicken at an engine rather than have a moving engine hit a stationary chicken, a fully featherd fowl (typically a 4-8 lb. chicken or cornish game hen) is launched (via a large chicken gun) at speeds of 140-200mph into a stationary engine test stand.

"Bird strikes can cause extensive damage to aircraft and serious injuries to their crews. At worst, they can be deadly confrontations. The Air Force estimates that planes hit about 3,000 birds every year, causing damages of $50 million and sometimes loss of human life. In a bird-strike accident in September 1995, 24 AWACS crew members were killed after takeoff from Elmendorf Air Force Base, Alaska. "

http://www.snopes2.com/spoons/legends/cannon.htm

So, you can see the chicken ingestion test is no laughing matter, even though it is often the butt of many jokes, whose punchlines consist of:

    ...you should make sure the chicken is thawed, first.

The chicken ingestion test is also describe in aero's WU under frozen chicken cannon.