A lot of the red fox dens I was at were filthy , animal parts scat ect. all around often you could smell them before you could see them . When it was lamb docking time you would know if you missed a fox den or two because the lambs would have part or most of their tails missing . Once the lambs got old and big enough to run fast the fox would just get a hold on the tail and it would pop off . That was one lamb that got lucky that time .