My last broody hatch was seven eggs I was hatching for a neighbor. He wanted the chicks immediately after drying off, so I would swap her hatched chicks with nearly two week old bantams that were clearly older that had been running around the chicken yard for a week. She is not people friendly and it was her first hatch, but she is a game hen x silkie. She acts nothing like a silkie, though. I just made sure that she could not see that I was giving them to her, and when she would peck at their wing feathers or look at them like she was considering attacking, I would divert her attention with treats or by rummaging under her chest, sometimes even passing my hand in front of her face. AND I did this in the day time. You just have to be careful about how you do it, and have fast hands. Nimue (the hen) is not stupid in the slightest.Why is it "hard"/stressful? I am on my 50th broody hen in just the last year. No stress at all for me and what seems like 50 happy broody hens to me. We only have around 100/102 days here and 115 is hot. You can simply break her broodiness, then you would not have to deal with it now.
"""I""" would not even try to put 1 week old chicks under a just started broody, even though she "might" adopt them---she is not stupid---she is going to know they are not hers. She "could" peck them to death----it happens----just according to the hen.