The circular nature of their march is just a result of their instinct to stay within the safety of their flock. In other words, what looks like extremely ominous behavior to human eyes is actually just a bunch of birds who can’t decide how scared they should be of roadkill.
It is very natural thing for this bird same as the turkey vulture in the sky when the circle around the dead animal on the ground , they want to make sure that it is easy to eat and go slowly from the sky circle and descend to it. While the wild turkey here are going around to make sure that if the dog , cat or road kill a life it will get confused as it is surrounded .
turkey when faced with an animal that might eat them, sometimes follow the risky route of actually approaching the predator. It can help signal to other turkeys in the area that there’s a threat, or help the turkeys evaluate how big of a danger the predator is.