If she's been broody for a week or more, you'll be able to get her to adopt. If less than that, her hormones may not be strong enough to make the switch from incubating to mothering.
Today will be three days. I'll probably let her go to the weekend and when I set the incubators again, give her whatever doesn't fit. I've never fostered chicks under a broody hen unless she already had babies. But usually if I move her covered at night when the hen can't see, when she wakes up on her new nest, she'll stay put. I don't dare let her incubate in the breeding pen. Too many snakes for that. And i just happen to have a roll of hardware cloth that I can put over the tractor to make it even more secure.
I would never do that now to Cookie because she is caring for 3 dozen.
My goodness! I've had large fowl hens with 2 dozen. I can't imagine a bantam with 3! lol I'll bet it is adorable!
I'll probably put less than a dozen under her. She's not gigantic, and if she breaks easily I don't want to lose a lot of eggs or chicks.
Speaking of chicks I've had four little Silver-laced and two Whites make it out. I had to pop them into the brooder this morning. They were making things very difficult for their unhatched brothers and sisters. I left the newest one in the incubator to finish drying up and letting the navel close completely. I saw another pip or two, but I think that I'm not going to get a really great hatch out of the N360 this first time. I didn't calibrate the internal thermostat, so I wonder if it was just running too warm. That would explain the early hatch and the DIS I'm suspecting. I also had a white pip and not make it out of the shell last night. It had died by the time I got to it this morning.