You have received some great advice from rebrascora and I just wanted to echo that I also like to give my broodys their own space when they are sitting and raising their bubs.
With my very first hatch I had hoped that mumma would be able to raise her little ones with the flock but the dynamics were such that the chicks risked injury and mumma and bubs were moved to their own little area.
Moving them does mean that you will have to integrate her and the bubs back into the flock when they are older but that works best for me.
It really does depend on your flock dynamics and the set up you have.
I actually replied and joined in on the thread as I wanted to respond to your latest post.
While a broody is sitting on the nest she is getting the bare minimum of feed and water which results in her losing some weight and condition. Then, after sitting for three weeks, she devotes herself to caring for her bubs with herself as second priority meaning her condition can deteriorate a little more.
So with your gal, if she has already been sitting for a month and you give her more eggs, that is another three weeks she will be sitting and then five to six weeks raising the little ones.
If it was me, I would definitely be trying to break her of her broodiness this time around to give her a chance to build up her condition.
If the new broody has only been broody for a couple of days, she would be the best one to give some eggs.
I also just wanted to echo rebrascora’s mention of parasites. A broody on the nest is a nice warm, stationary food supply for lice and mites and for that reason, again just my thoughts, but I would probably start off with a fresh nest for the new broody and eggs or at least ensure that the nest, which sounds like it has been occupied for at least four weeks, is dusted.
Good luck and please let us know how you go?