All chickens are leery of strange chickens at first, even baby chicks. That's why you introduce them gradually and with barriers to prevent the sort of nasty scenes you are envisioning.
If you're planning on raising baby chicks, the easiest thing to do is brood them right in the coop or the run, if the coop is lacking in space. It not only gives the chicks plenty of room to develop, it affords the adult chicken(s) the opportunity to gradually become accepting of the babies. (See the thread on brooding with the heating pad system "Mama-Heating Pad for the Brooder")
After the chicks have reached three weeks of age, I then open small chick-size openings (5 x 7") into the rest of the run. The chicks then mingle with the adult(s) and run back to safety when harassed. This panic room system has been successful for my chicks for going on nine years.
Note the flaps on the hinged door frames. It helps to be able to close them when you need to confine the chicks to their safe pen for some reason, such as you aren't there to supervise the early excursions into the adult flock.
This system allows introduction of the chicks at an early age when they're still small enough to present less of a threat to any adults in the flock. Acceptance occurs earlier because the chicks have been part of the flock by proximity from the very start, and the chicks have been learning while observing the adult behavior and are better equipped to understand the dangers involved in becoming part of the pecking order.