I was a nervous wreck the first time I let a broody hatch. Seriously my blood pressure must have been off the charts and I probably appeared deranged. But in the end, I let her do her thing, she did admirably, and I learned not to worry so much. The vast majority of the time, they actually do know what to do, and they do it well. Hell hath no fury like a broody mama, she will protect them. I move my broodies to a parallel 'nursery' run that I put in just for this, but I move them as I said, when they start to sit. I have multiple roosters, so I don't take the chance that she would be outnumbered in trying to protect them. Can you put up a temporary fence to separate her until hatch is done and everyone is dried out and moving about?