at this point they are too old for the hens to mother them but young enough that they shouldnt fight with the older hens in the pecking order, they will most likely just stick with there little group and not bother any body.i would personaly let them out with the older girls acouple hours a day while your there for two or three days untill your sure your hens wont gang up and hurt/kill the young ones and i wouldnt let them out in the yard right away because they would need time to learn where there new coop is and that they are supposed to go in there at night. they should know by now to hide from hawks and such but if you do choose to let them free range right now be prepared to go looking for them at or before dusk because most likely they will all go hudle together under a bush or in a tree. good luck!!