i was wonder why my brown leghorn and black australorp keep on bitting my two new baby chicks what wrong with this
I'm not sure what your citizenship has to do with this issue - but the other answers you received are good ones. You should separate them if they are very aggresive, but pecking at each other is normal. The older ones are just trying to tell the younger ones who is in charge - it's perfectly normal and expected in the chicken pecking order. Separating them because of occassional pecks will cause your integration time to be lengthen because you'll just have to keep removing them over and over again.
Personally I would leave them alone - without the extra wiring and make sure there are enough feeders and waterers so that everyone can eat and not keep the others from getting food. Make sure there are "places" for the little ones to hide or get away from the bigs when they need to. I free range mine outside the secure run during the day so they all have their areas where they hang out. But if you only have a small run you can still add things like trash cans or other obstacles near the fencing but not up against it - with just a small enough area for the littles to squeeze behind if being chased, but the bigs not be able to get back there.
They will settle down once the bigs feel like they have established the order and the littles understand who to avoid.
