SILVER FOX FARMING. 
13 
digging out, the fence is either extended into the ground (fig. 17) or 
turned abruptly inward at the surface (fig. 18) to form a mat 3 feet 
wide, the inner edge of which is pinned firmly to the ground and 
usually covered with earth or stone. A fence extended into the 
ground must reach a depth of 4 or 5 feet if the soil is soft, and be 
turned inward a foot at the bottom. If there is a subsoil of clay or 
hardpan, the fence need not 
enter it more than 6 inches. 
Instead of netting, the under- 
ground part of a fence may 
be made of 2-inch creosoted 
planks. As foxes climb wire 
fences readily an inward over- 
hang about 18 
inches wide 
should b e 
placed at the 
top to prevent 
escape (figs. 
15-20). When 
fox has 
scrambled up 
to an overhang, 
its only means 
of descending 
is by falling. 
Fig. 9. — Double-walled den; exterior broken to show inner den (see figs. 7 and 8). 
Sometimes valuable animals have been seriously 
injured in this way. To prevent accidents of this 
kind an intermediate overhang is sometimes constructed 5 feet from 
the ground, as shown in figure 16, or a smooth zone of boards or 
sheet iron is inserted in the upper half of the fence, as shown in 
figure 20. 
The yards for sequestering males are usually adj acent to the main 
yards, with which they are connected by a chute having a sliding 
door (fig. 21), though sometimes they are separated from the family 
