At many egg farms, chickens that are too old to produce are suffocated with carbon dioxide and then dumped in a compost heap. Apparently though, "zombie birds" that managed to survive have been spotted emerging from mass graves at Northern California farms. Now that slaughterhouses in the state have stopped accepting the unwanted birds, farmers say they have no choice but to compost them in sawdust. From the Associated Press:
A food bank proposed making sausage to feed the poor. A reptile enthusiast suggested using them as food for large exotic pets like pythons and alligators. And an industry group said in the future they could be used as fuel for power plants...Link (Thanks, Paul Saffo!)
The egg-laying birds have only a pound of usable meat, compared to the 5-pound chickens typically raised for eating. Slaughtering the chickens, even to transport them unprocessed and frozen whole, would likely cost more than composting them, (said Petaluma egg farmer Arnie) Reibli.