So far as them being flighty, they'll likely settle down. If you are trying to pick them up, then yes they will seem flighty. Chickens just don't naturally take to that in general. You will get one or two here or there that does love it w/out extensive handling though. One of mine is like a pet dog. She was raised no differently from her two sisters yet is the friendliest out there. She will come when I call her, go where I tell her, and allow me to pick her up with little fuss. Whatever I'm drinking out of a can, she drinks some too. She even comes in the house when I allow it and follows me around talking to me.
Recently I moved and she wanted to be near me. Not her flock, though she is once again the top hen. But me. For security I suppose. She had a rough time right after moving with a stuck egg. She came to me and "told" me of it so I dosed her rear with mineral oil. She hated that but put up with it again, with minimal fuss. She was not handled extensively as a chick. She's just naturally really friendly. Sometimes you get one, sometimes you don't.
So far as the one that seems mean at 3 1/2 months, they do go through an "aw Mom don't touch me!" stage when they are getting ready to lay. Then after laying a bit, settle down and get a lot more calm. I can't imagine hitting one of my hens or pullets with a pipe or anything else like that. I've been known to tap them hard on the back of the head but only with my fingers. NEVER a pipe or stick. Never.