I've read many places that you should wait till night because they are more docile and then by morning they've already had the whole night together cheeping.
But today I placed some chicks under my broody who really wanted to be a mom and she took to them right away and I just checked them a bit ago and she's got
everyone tucked under her wings. but my other broody that I also wanted to give a chick too who is an american game who is alittle more wild jusut wanted to get away from me and pecked at the baby, so I took the baby away and gave it to my other broody who is a buff orp. My buff tried to hatch out some of her own but they didn't survive to hatch and it had been about 30 days, and she was always fluffed up when eating or if I was too close and was always clucking. So my opinion is it depends on the bird themselves. I just kept a close eye on mine and stayed near till I knew she wasn't going to hurt the babies. Good luck.