It appears that the government has been ready for this day a few years ago as they bought some mobile gassing units to take the birds out as quickly as possible. The Soviets used to just inject car exhaust into the unit, but it looks like they use separate tanks to do the killing in the US. I wonder why the USDA doesn’t use car exhaust too? Here a guy talks about it:
The mobile killing units are ready to roll. If you see something like this in your neighborhood, you should know what to expect.