In the past, you could send game through the Royal Mail--provided that it wasn't leaking:
In 1936, Post Office rules stated that game, including rabbits, could be posted with nothing but a neck label as long as ‘no liquid is likely to exude’. The postman here is holding some unusual mail found in the Returned Parcels section at Mount Pleasant sorting office, London.
Link -via TYWKIWDBI | Photo: Royal Mail
http://pe.usps.gov/text/pub52/pub52c5_007.htm