That depends...on the adults and room in free range...and to some degree the temperament of the chicks. It is a process.
As to the age of the chicks, my broody hatch chicks are out free ranging with the adults, depending on hen and brood, anywhere from 3 days to 2 weeks of age. Momma protects them and integrates them. So the babes are well adapted for free ranging with the caveat of PREDATOR PROTECTION. The cheeping of little babes is like a magnet for hawks, rats, cats and other predators. You will also need to "stupid chick" proof your area to prevent drowning in a water bowl or wandering off and getting stuck.
Good news at 5 weeks of age, most of them should be sized enough to avoid most pitfalls other than predators. However flock acceptance, to non-broody hen babes, can be a problem. It is for this reason I tend to wait until 8 to 10 weeks of age, or at least until the babes are half the size of the adults. It can avoid some hazing problems and "stupid chick" problems.
In your situation, the adult reaction is the big hurdle. With hen brooded, momma makes the introductions and will fend off any aggressive hens. Also a good rooster should help integrate. Having neither of those (I assume), since you have a group of them (7), they will make a subflock. It sounds like they have had fence exposure, so they are not unknown to the adults.
Placing them in free range is a good way to help them integrate with the flock without forcing them into tight quarters at the mercy of an overly aggressive adult. Be sure to have numerous feeders and waterers so they can't be hazed away from them, and hiding places should a bird become overly aggressive.
Then there is the round up at night. Be prepared that you may need to train the babes to go in with the adults. Expect much drama in the coop at night as they tussle for roosting space. Generally the babes are hazed away from the roosts, which can push them out to the run or yard. Sometimes you end up plucking babes from bushes and fence posts if they have been pushed out of the coop by the adults.
If you have a separate coop for the babes than the adults, you can get nicely segregated flocks (babes in one and adults), or a mixture, or suddenly no one seems to remember where to go.
All to say, if you think the babes will be well enough received by the flock, you can begin free ranging knowing you will have some issues which may arise.
Again, if I've separately brooded a bunch of chicks, I personally prefer them to be a bit bigger (8 to 10 weeks) to find easier transition. The smaller the chicks are the more problems seem to arise which are mentioned above.
My thoughts.
LofMc