Conservationists are calling for an investigation into plummeting badger numbers in the run up to the cull.
The apparent 50% decline over a year before the cull started appears to be unprecedented, data from other badger populations suggests.
Government officials have blamed the cold winter, disease or lack of food for the dwindling numbers.
But a wildlife charity claims illegal killing of badgers may behind the fall in numbers and is calling for answers.
Meanwhile, reports on social networks suggest protestors have been interfering with the hair traps used to assess badger numbers. This could potentially lead to errors in population estimates.
There have been three official attempts to count badgers in west Somerset and west Gloucestershire in the run up to the cull.
The first estimate - in October 2012 - concluded there were 3,644 badgers in west Gloucestershire and 4,289 in west Somerset.