Don't let yourself fall in love with a baby roo. It's a recipe for heartbreak. Among the many generations of pullets I've raised, I'd say they more or less stick with their baby personality, with few exceptions. And the exceptions tend to be in the favorable direction. The ones that start out friendly, tend to stay friendly, and among the more skittish ones, some will come around and get friendlier later in life. They all have a "cooling off" period once they really hit puberty, where they want their independence and won't be all up in your face like when they were chicks. But they'll be the same way with their broodmates, too, so don't take it personally. When they are young, chicks will huddle together for warmth and company, and sleep in piles together even when they no longer need the warmth. But as they grow up, they will do less and less of that.
Major life events can kick them into a friendlier gear, too, if it involves additional positive interaction from you. For example, one of my more skittish hens needed medication at some point after she grew up. Twice a day, every day for weeks, I would grab her and take her out of the run for some one-on-one time where I'd feed her scrambled eggs laced with medicine. She LOVED it! It became our special time together. She got less skittish about being picked up and handled. And she continued following me around and expecting something special for years after her treatment ended. Another skittish hen turned out to be a great broody. I'd bring her scrambled eggs and hand feed them to her while she sat on her eggs. Again, it became "our thing". Then I brought some to the chicks, and she'd teach them to eat from my hand. Later she'd teach them how to be proper lap chickens, by sitting in my lap and calling them over. She had never been a lap chicken herself before that. But I was an ally among a flock of (what she considered) enemies, beating them up if they got close to the chicks, but being totally cool with me picking the chicks up and interacting with them. She's raising her 4th brood for me right now, and we still have our special bond. She has kept her lap chicken status even when she doesn't have chicks, and comes over to hang out with me every time I go in and sit in the run. Her sister of the same breed and brood, who had the same personality, has never been broody and still runs from me if I get too close. So that was a major personality adjustment there.
