Shade
Monster Junkie
Well, there are some mass death assemblages of Aetosaurs (e.g. lots of fossil aetosaurs that seem to have died at the same time), suggesting at least some of them gathered in groups. There's a mass death assemblage with 24 specimens of Aetosaurus.
I think that's enough to give them "herd" organization. Maybe 4-24?
Works for me!