Behavior in preowned chickens.
Feed is the great equalizer. Walk slowly and talk softly around them. Feed small amounts of feed several times daily until they come to learn that you are the 'provider of feed'. Once they calm down and accept you, provide feed ad lib.
A lot depends upon breed. Some breeds are naturally more flighty than others. They may never become fully tame, but their behavior should improve over time.
They are also in unfamiliar territory being in a new place, so they will be skittish.
Find treats they like. Mine adore millet in commercial bird seed, and black sunflower seed.
Be liberal with the treats at first, calling softly "cluck, cluck" walking slowly. Toss the treats away from you so they see that it is good to eat. Stand back and let them get used to eating the treat. After a week or so, they usually are anticipating you coming out. They will start to gather when they hear the "cluck cluck" call.
Then you can start feeding closer and closer to your feet. Usually somebody gets brave and takes the treat, then the rest follow. If you really want to work on it, after they are comfortable at this level, bend down slowly and hold your hand out to them being very patient as most will run back away. Somebody usually is brave and will start to take from your hand. Keep doing that and in time the others usually follow.
But not all chickens become hand tamed, which is fine with me. I am happy that they all coming running when I shake the treat bucket and call "cluck cluck." I can direct them anywhere I want them to go leading them with the treat bucket this way.
Good luck with them. With patience and a little time, I think you'll be pleased with the results.