I did some more reading about turkey vultures, and learned that they roost in large community groups but tend to forage independently during the day. So my early guess that a group seen together in early spring suggested the previous year's family unit is not necessarily right at all. But it's interesting to learn that they are communal birds.
The bird on the far right, above, is spreading its wings while resting. This is a common stance for the turkey vulture and is known as the "horaltic pose." The Turkey Vulture Society says:
The stance may serve multiple functions, including warming the body and drying the wings. Research on this pose suggests that turkey vultures spread their wings in the mornings, once the sun's intensity reaches a certain level, to raise their body temperature (which they lower at night by a few degrees as an energy saving mechanism). [see Turkey Vulture Facts page]This photo was taken at about 4:20 p.m., for what that's worth.
If you see turkey vultures circling in an area, it does not necessarily mean there is a dead animal nearby. The same site says, "Circling vultures may be gaining altitude for long flights, searching for food, or playing."
I like the idea of such large birds playing.