Do we know ‘raptors’ hunted in packs?
The short answer is no, not necessarily, but the best evidence that some of these kinds of dinosaurs at least moved in social groups comes from trackways. ‘Raptor’ dinosaurs leave distinctive footprints, owing to the enormous killing claws on their middle toes, which don’t touch the ground because the dinosaurs held them upright. Paleontologists have found trackways of these kinds of footprints arranged beside one another, tracking the same course, deviations and all. That means it’s a pretty good bet they were moving together.
As far as fossil remains go, we can’t always take them at face value. There’s a famous fossil assemblage from the early-middle Cretaceous Period with a Tenontosaurus (a big plant-eating dinosaur related to the duckbilled dinosaurs) surrounded by Deinonychus (a ‘raptor’ dinosaur which provided the inspiration for the raptors in Jurassic Park). Many of the Deinonychus’ teeth were broken off into the Tenontosaurus, and that’s where the whole pack-hunting idea started in the first place: multiple Deinonychus appear to have died attacking Tenontosaurus all at once, and Tenontosaurus was almost certainly far too big for an individual Deinonychus to attack anyway.
But the fossil remains of a Tenontosaurus surrounded by Deinonychus can also be compatible with a scenario where the Tenontosaurus died on its own and a bunch of Deinonychus mobbed its carcass feeding-frenzy style, the way modern Komodo dragons mob water buffalo carcasses. And if we find a bunch of predators together and no prey, it could just be that they were all washed into some basin after death and didn’t actually die together. Or even if they did, they might have all just been drinking at a waterhole and gotten caught in a flash flood (one of the few forces that can kill and move multiple dinosaurs all at once).
In short, some of the ‘raptor’ dinosaurs probably moved together at least some of the time, but it’s hard to say for sure whether they actually hunted together.