Quick ? about when to put chicks with hen

I have a hen that has 3 chicks already. These are 3-4 or 4-5 days old, can't remember which. I brought the rest of her eggs inside when she left the nest.

Now I have 4 chicks inside, and one pipped egg. 2 chicks hatched today, one yesterday, and one the day before.

I was going to take the 2 oldest ones outside and put them under the hen, and the others tomorrow.

Should I just wait and put all them under her at the same time?

The two newest ones are still pretty weak, and there is 1 not hatched yet. I had to seperate the 2 older ones, cause they were picking on the younger ones too much.
Thanks!

 

Ok well it's late, and I am not sure, so I guess I'll wait till tomorrow and hope all goes well...