Handling makes a huge difference in birds. I gave two leghorns of of of my batches to a little girl who held them all day and night. Well, when her mate got eaten by a coon 4 years later and I got the other back, it was the fattest calmest leghorn I have ever seen. All mine were raised as livestock and would come for food and run if you looked at them wrong. This one loved pet was not only well fed and fat, you could reach out to pick her up, poke her side, lift her wing, grab her leg, hold her on her back, flop her comb around, and she'd just stand or sit there like nothing was happening.That bird had some serious handling and cuddling in it's time and was like a living rag doll. She didn't lay eggs but due to her temperament, she went to a pet home vs where the rest go.
The rest are like that. But I brought them up as chicks. You can pay your lap and they'll jump up and sit and like to be petted. These came from a home with 40+ chicks so I think not very much handling was done. I continue to pick them up and hold them. I think they're getting calmer. These things just take time I guess!