My silkie broody has seven babies under her now and I have some hatching in the incubator now. was hoping for two to hatch and was going to put them under her but it looks like I could have five,is that to many for her keep warm, it would be 12
I had a silkie that managed several dozen but she had a heat lamp to assist her. It was amazing to see her try to shove all those babies around her body...lol. She hatched a clutch in the winter and I had eggs in the bator at the time. Probably close to 3 doz all about the same time. She took the new babies in and they all flocked to her as mama.
I had brought them inside to a cool mud room, not heated but not freezing...extended warmth from the house and again I used a heat lamp at one end of the large broody box so they all gathered where they felt comfy. Didn't lose any of the babies as I recall.