This was at the Northern part of the Borders, in those parts anything on feet was liable to disappear in the night.
One old reiver on passing a soo stack was heard to mutter " man if ye had feet ye widna bide lang here"

A soo stack was a stack of hay or oats built in the shape of a house with a pitched roof.

An ancient name, a soo having been used in medieval times to protect men in their endeavours to gain access to castles and keeps. It helped shed the molten lead etc. coming from above. ``````````````````````````````````````````````````````````````````