For thousands of years, even before they were domesticated but also on farms around the world after they were domesticated, hens have been hatching and raising chicks with the flock. For many of us a broody hen hatching and raising her chicks with the flock is by far the preferred way to go. But there are also a lot of people that isolate the hen while she is hatching and/or raising the chicks. Just like practically everything with chickens there is not one way that is right for everyone while everything else is wrong. There are multiple ways that work. Sometimes certain things work better for certain people for various reasons. And something that is often missed, there are risks no matter which way you go. Dealing with living animals is like that.
There are some things to consider. How much room do you have? In general the more room you have the easier any of this is. What is your flock make-up? This is pure personal preference but I like having a mature rooster in the flock. Most mature roosters either help the hen raise the chicks or as a minimum do them no harm. What risk you have from adults is almost certainly going to come from the hens or immature chickens, pullets or cockerels.
In spite of a lot you read on here, if you have sufficient room the other hens don’t offer that much of a threat to start with. When a threat done happen, my broody hens have always been very capable of protecting their chicks. Others have had some problems with that. When you deal with different living animals in different set-ups and flock make-ups you can have different results.
Whether you elect to let the hen hatch with the flock or not, collect all the eggs you want to give her and start them all at the same time. Starting them at the same time is very important so they hatch at the same time. You see some stressful posts on here from people that don’t start them at the same time, the staggered hatch drama can get pretty thick.
It’s always a good idea to mark the eggs you want her to hatch, I use a black Sharpie and draw circles the short way and long way so I can instantly tell which ones belong. If the broody hen’s nest is open to the flock, it is always possible another hen will lay an egg in her nest. You need to check under her each day fairly late in the day after all of them have laid and remove any eggs that don’t belong. As long as you remove them daily, they are fine to eat. There are two main reasons to collect hem daily. One is to avoid staggered hatches. The other is that if the eggs build up to where she can’t cover them all, some can get pushed out, cool off, and die. Then that egg gets pulled back under and another is pushed out to die. Not good.
If you let the hen raise the chicks with the flock, she will handle integration for you. The chicks will still have to handle pecking order issues themselves as they mature but at least they are integrated. This I another area where room is important. The more room they have the easier it is for the chicks to handle those pecking order issues once they are weaned. But if your room is that tight you will probably have integration issues when you try to integrate them if you let the hen raise them separately.
In my opinion here is no right or wrong way to do this. There are many different variations on the general theme of allowing the hen to do all the work for you or doing part of it yourself. It’s your decision which way you want to go. Good luck!