I’d move them to the coop tonight and leave them locked in there for a couple of days. That should be long enough for the hen to start taking them in the coop at night. If the dog crate is big enough and you make sure there are no openings big enough that the chicks can get out away from Mama’s protection, you could leave them in the dog crate. Or maybe build a temporary pen for the hen and chicks for a couple of days. That way your other chickens can come and go.
Canoe, many decades ago when I was growing up on a small farm way back in the Appalachian ridges, our chickens totally free ranged. Some slept in a hen house and some slept in trees. That hen house was never locked at night. The hens hatched chicks in the hen house or often hid a nest in really strange places and hatched those. The hens were left alone to raise them. That’s pretty much how all the small farmers in that area handled their chickens. That’s pretty much how small farmers have been handling chickens for thousands of years.
As far back as I can remember until I left that farm at 18, I can remember two predators that had to be dealt with, a dog and a fox. Only two. We all have different predator pressures and different tolerances. I can’t raise mine that way because too many people drop dogs off out here and I get substantial losses. I don’t want to minimize the threat from predators. Many of us could be wiped out today if we didn’t take precautions. I take predators seriously. But from how I grew up I’m not at all surprised that those chicks have not been killed by a predator. It could happen today, it might not happen for years. But yes, at some point, there will almost certainly be losses.