Anthropology is the study of humankind, culturally and physically, in all times and places. Forensic Anthropology is the application of anthropological knowledge and techniques in a legal context. This involves detailed knowledge of osteology (skeletal anatomy and biology) to aid in the identification and cause of death of skeletal remains, as well as the recovery of remains using archaeological techniques.
Most forensic anthropologists in the US are university professors who work on casework as it comes to their university. Some work for, or as consultants to, city/state/federal government - for example, in a medical examiner's office, or in a governmental lab.
Yes, there is an outdoor field laboratory investigating postmortem change, which has often been called the "body farm". The proper name for this field laboratory is the Anthropological Research Facility, and it is operated by the University of Tennessee Knoxville. The University has been trying to get away from the unfortunate term "body farm", as it is disrespectful to those who have generously donated their bodies to the study, and to the researchers who carry out there work there. The Research Facility was founded by Dr. William Bass in 1972, and the studies carried out there have been invaluable to the field of forensic science.