Our broodies tend to have minimal flock interaction when they are setting also, just happens that way... since when they get out for their daily most of the flock is out free ranging. For 're-introducing' we generally allow the broody and new chicks to be in an area of the run or coop which is only separated by hardware cloth or chicken wire for a few days, then the barrier is removed and mama can range where she wants with the chicks. Since our flock is broody friendly we worry even less and a few of our experienced broodies hatch where ever they want and are free within the coop/flock from day one...
Since the weather is nice and the flock is out and about most of the time the interactions between broody and flock are actually short term and everyone has room to retreat if there is a conflict. We don't interfere really... they seem to work it out on their own pretty quickly. The key is making sure there is room to retreat and enough food and water sources to avoid conflicts.
Generally the older flock members will 'check out' the broody and her new crew from a distance, then approach for a closer look but not get pushy about it, within a few days to a week you rarely even notice any posturing anymore.
If your flock is new to broodies and chicks then you will need to make sure that early interactions are closely monitored to see if there are any aggressive flock members you need to intervene with. A peck here and there is to be expected... since the little ones need to learn to follow the rules just like the rest of the flock and are subject to pecking order issues also... it is active stalking and/or unrelenting aggression which needs immediate intervention. Mama will take care of much of the protection, but may need some back up if she is inexperienced, smaller then the rest of the hens or really low on the pecking order.
