Talking a little about den site location.
Fox don't seem to care where they den.
Last year driving home from work I had to slow down to avoid from running over a fox
and the four little gray fur balls following her.
The next day I located her den. It was in a colvert on a approach leading to a old gravel pit.
The den was only about 12' from the white line on a little used county paved road.
The fox family stayed there for a week or ten days. By that time the little fox lost all their gray fur and were red.
Years ago I was driving down a dirt county road. The road turned and headed down a hill. Out the side window I spotted a pup fox watching from his den. I could have touched him with a broom stick.
The den was located in a bank, on the inside corner of the road.
When I was a kid, I heard a story about a local sheep rancher
who had gathered his herd of sheep and put them in a small pasture next to a pen where he docked the lambs.
While working the lambs he looked out into the small pasture and spotted a pup fox
in the middle of his sheep. His blood pressure jumped a tad
Turns out there was a fox den in the middle of his small pasture.
Hal