I don't know about Oggie's psychology, but the point of the body farm is that people donate their bodies upon death to forensic research, just as some people do to medical research. These bodies are left in various states of burial or completely exposed to the elements so that the scientists can moniter what happens to them over periods of time so that when a body is found in suspicious surcumstances they can help the police to determine how long it has been and where it has been, etc. There are no real body farms in the UK, but I believe there is one in Virginia, USA.