There are diseases that inflict deer when they are gathered in high concentrations.
The PGC has been making the same claim for many years, but the funny thing is we have never had an outbreak of disease that was the result of high DD. Also, even in Valley Forge with a DD of over 200 DPSM, the herd has not suffered from a disease that is transferred from deer to deer.So the threat of disease seems to be a red herring the PGC tries to use to justify HR just like they claimed our buck age structure was a problem in order to justify ARs,when in fact ARs were implemented to get more rapid HR.