I like to observe broody hens and chicks. When a hen hatches, the first to hatch often spend a full day or full two days under her before she brings them off of the nest. They will move around some but are mostly under her. After she brings them off of the nest they will eat and drink, but they seem to spend a lot of time under her for a day or two. After a couple of days they run around a lot more.
At the age you mentioned yours are pretty much doing what I'd expect. I don't see any red flags at all. Good luck!