A good mama protects her chicks from the others, pecks and/or runs them off, for a few weeks, anyway. One time I thought I saw a spot of blood on one chick. By the time I got back with the BluKote I couldn't tell which one. Of course mama pecks them a little, too. A good roo will also help protect the chicks -- if he is a good one.
Not all mamas protect well, and some hens are much pushier than others about chicks. There are no guarantees, of course. Heck, I caught one broody killing her chick as it hatched (lost the whole hatch.) I've had 5 other sets of chicks raised by a broody and not lost one to another hen yet. Knock on wood. First time I did it, I didn't know it was said to be a bad idea, before I found BYC. Integration at adult size isn't guaranteed to go well, either, so this is just my preference, at least for now. Apparently, in nature, mamas hatch them in hiding and bring them to the flock at a few days old. Or at least I've heard and read lots of reports of this happening.
I have seven 6-week olds running around with my flock now. Their mama abandoned them a couple of weeks ago. They hang around together and have learned not to compete with hens for treats, which I spread around so everyone gets some. I would be very surprised if I lost one to another chicken at this point.
Good luck whichever way you go.