I like the animal connection, because it ties the construction down to a practical use as well as/instead of a purely ritual one. Without that, you have to wonder how the construction was so universal and widespread.

How about a pound? Lots of village ones are round (I wonder why that is?)

Or maybe the animals were sacred?....

I like the idea even more regarding stone circles - rot proof supports for fencing. Maybe not Avebury though!

I think I'll add it, when I get the chance.