How deep for an outdoor enclosure footing?

[fgately]

I am starting to build the outside pen for my three russians. I will bury a row of concrete block so the torts cant dig out, but more importantly, other critters can't dig in.

How deep should I dig down?

 

[Fernando]

I'd say 8 inches.

 

[Laura]

are you going to line it with wire? or just the edges?
I have trouble with gophers coming in.. the edges.. i would go down at least 6 inches.. they dont burrow too deep.. at least mine doesnt.
he has climbed out a few times!