I use to live near a Kosher chicken plant (well, in the same county), and knew quite a few people who worked there.
The plant had LOTS of Rabbis working there, who blessed the chickens prior to having their heads pulled off (the chickens, not the Rabbis).
The "Blessing of the truck", mentioned above, was used if the original truck/trailer broke down or was in a wreck and the meat had to be reloaded into another truck/trailer.
Hope that cleared it up for ya.