Hello louclare. I have no experience with broody hens, but I have read about others on this site who successfully put fertilized eggs under a broody hen to hatch. They may need a broody area, however, separate from the rest of your flock. Hopefully others on this site will come along to give you more information on this. If you go with day old chicks, I believe you will need to keep them in a brooder until they are fully feathered, and integrate them into your flock only when they are about the same size as the other chickens in your flock. If you try to integrate them when they are smaller in size, they may get pecked to death. Here is a link from this site with more information about integrating your flock. You will also find a wealth of information on this site by clicking on the Learning Center link on the Home Page. Best of luck to you! https://www.backyardchickens.com/web/viewblog.php?id=2593-adding-to-your-flock
Do you want friendly chickens that are very tame or will you mind that they aren't real people-friendly? That is one big difference between brooder-raised chicks and broody-hen raised chicks.
Personally, I go for the people-friendly chickens myself. To get the tamest chicks, I put the brooder box up on a table and construct an access into it from the side rather than the top, as most people do. When you have a brooder box down on the floor, reaching in to handle the chicks from above, it frightens them due to their instinct to fear predators attacking from the sky. You can't handle the babies too much, the more the better. It makes for very tame chickens that will be very easy to catch whenever you need to.
When it comes time to merge them into the adult flock, I've found that if you set up a temporary nursery pen inside the run and begin letting the chicks spend nice days outside in this pen, you can begin introducing them as early as three or four weeks of age, or as soon as they're feathered enough to handle temperatures down to 70-75 degrees. Keep their pet carrier in the nursery pen so they can use it to nap in and as a security blanket.
When the chicks are around five weeks old, and have been getting acquainted with the older chickens for a couple of weeks, I cut small pop holes into their pen so they can begin to explore the bigger world, and learn the pecking order. Even though they're still very small, they quickly learn to run back to the safety of their nursery when chased or bullied, and their food and water is also safe from the older flock since they can't fit through the pop holes. Of course they're still spending nights indoors in their brooder.
At six weeks, I move them into the coop. I wait until the others are done laying for the day, and I put the youngsters into their new home several hours before roosting time. I keep the older ones out until the very last minute, and let them in to roost. If the babies haven't figured out how to get onto the perch, I place them up there. Usually the older ones will roost with very little fuss over the new-comers since they've already learned over the last few weeks that they are members of the flock.
You might need to help the tykes find their way out in the morning, but that's less of a problem than learning to go in at night since the older ones will chase them out. It's at roosting time that you may need to play mama hen and teach them how to go in for the next week or so until they get the idea. There's a chance that it won't work because they're still too immature. Put them back into their brooder, and try again in a week.
It's really not that hard.
If you elect to let a broody raise them, she may need to be kept safe from the rest, but she'll usually take charge of protecting them and teaching them flock behavior.