Live transport about 35 miles and then in some cases another 50 miles for further processing.
Raw (frozen) meat as far away as Brazil! Shipped into Rotterdam and then an artic to the UK processing plant.
It's the miles in the next link of the chain - from processor to store - that are the killer. The chicken isn't using much fossil fuel while it's still alive, the moment it's dead the use ramps up; refrigeration, packaging, artic fuel. It's why the environmental attention needs to be on what goes on in the food chain, rather than on farm.