They were creepy, and to the observer they may suggest a human shape, but they really didn't mean anything specific - which may be why they were so creepy, the enigma of them.
Were they small symbols of the 'witch's' victims?
Were they an attempt at some stylized pentagram, or more accurately a pentacle?
Were they the personal sigil of the witch, markers for her territory?
Were they warnings made by other people to ward off traveler's from the witch's domain?
Who knows?
I like the idea of a few being hung with other things, like mobiles made of bones and feathers, witch jars lit with candles, animal skins, kitchen utensils like giant ladles, cleavers and forks...
and bags, bags with something twitching inside.