A chicken farmer in the next valley kept a lot of chickens right around the right weight. When he got word there'd be a chicken shot the next day, he'd pick out a bunch with the right weight, then make sure they ate just the right amount overnight.

He'd put twice as many as needed in his truck and run them to the shot site. At least the needed number would have shit themselves down to spec weight.

Procedure is to anesthetize the chicken (must be alive at impact) and stuff it into a paper machet projectile. The air canon could get the chicken up to over 400mph at impact. You clean up with a hose and a mop.

The U.S. government spent a lot of money trying to develop an artificial chicken, but was not successful.