Impossible that this should be continuous for 12 days. They never stop to eat or drink?
They start off with just standing in a random mob. How many dropped dead in that 10 days.
Sheep are renowned for following the leader, so if the leader goes in circles the mob follow.
I must say it seems emblematic of the behaviour of many humans.
Yeah, color me skeptical about the 12 days. It looks like it does happen for a time, but no evidence this was for 12 days. Also, it is interesting that not all do it (some even just stand in the middle), and there is clearly something different about the ground as there is a circular patch.