Totally normal phase for them to go through. They're becoming teenagers and therefore more independent. As chicks, they saw you as Mama. At this age, they would have been kicked to the curb by Mama and be learning to fend for themselves. They have a strong instinct to avoid all predators. And, even though you raised them, and had that Mama relationship with them, you do RESEMBLE a predator. So, they'll keep their distance. As they come closer to sexual maturity, and as you continue to provide good things to eat, they'll come back to you, this time, seeing you as their Alpha (rooster) Before those first eggs, they may run up to you and squat in front of you. Do they have food in front of them all the time? Try feeding them only 1 - 2 x/day. They'll be sure to come running when you bring their food. Always use feeding time as a training tool. Use a signature call for them every time they get food, so they will learn to come running when you call them. This is an excellent tool to use to train them so you can put them back in their run or coop after they've been free ranging.