When they learn their place, the pecking will decrease. Do you have roosts that are all one level? If you do, this creates a situation where the lesser hens are having to roost next to and on the same level as the higher ranking hens....this creates more problems for them. Set up roosts where the lesser hens can roost below and away from pecking reach of the others and it may help things.
For feeding, feed in a trough that is long enough that the new hens can eat without being pecked away from the feeder. Then feed in meals, so that the other chickens are too busy getting their food to bother driving the new ones away from the feed.
Put some roost bars or stumps out in your run so the new hens can get up and away from the other hens. All of these things can help. But, in the end, that's the social life of chickens, particularly when they are all penned together and cannot get away from the others.