While you have them in the "no touch" situation, I'd like to make a suggestion. What I do is feed them together but separate. I know that makes no sense, but if you take some scratch or other treats out there, run a line of it on the inside of the isolation cage and another line of it on the older chickens' side, they end up feeding head-to-head peacefully, so when they are integrated here is no fussing over food. The wire of the separation keeps them from aggressively pecking at the intruders taking "their" food. Chickens can get very territorial over food and water supplies. I also hang the chicks' feeder and waterer and the adults' containers side by side, separated only by the wire of the divider for the same reason. When I integrate, I have more than one feeding and watering station - they can't guard them all so I know that the newest chicks are getting to eat and drink.
It's a rather unorthodox method of raising older birds and chicks together, but it works for me. My chicks are brooded outdoors in a wire brooder pen within the run from the start. After some initial curiosity, the adults hardly even notice them anymore. By 3 weeks old I'm mingling them in the run, and by 4 weeks old I have total integration and the brooder pen is torn down completely. These are 4 week old Silkie chicks, fully and peacefully integrated with my flock of standards. Conventional wisdom says to integrate much later than I do.
It's a rather unorthodox method of raising older birds and chicks together, but it works for me. My chicks are brooded outdoors in a wire brooder pen within the run from the start. After some initial curiosity, the adults hardly even notice them anymore. By 3 weeks old I'm mingling them in the run, and by 4 weeks old I have total integration and the brooder pen is torn down completely. These are 4 week old Silkie chicks, fully and peacefully integrated with my flock of standards. Conventional wisdom says to integrate much later than I do.