Broody hen! My first and hers! Umm.... help!!

[chookalina]

Ok, so one of my hens has decided to lay on about six eggs, and while I discouraged broodiness all winter, it is now mid-march and I figured, well heck, let her give it a try.
We have a dozen nesting boxes in the henhouse, 15 hens and two roos. I am dreadful with dimensions, but I would say the henhouse is about 100 square feet. Ok, it is a rectangle, but you get my drift!
They have a fairly big outer run that they always have access to, in the spring and summer they are free range all day with acres to run.
Now, do I have to somehow cordon off an area for my broody girl if she actually manages to hatch her eggs? Our roos are very randy, so I am thinking at least a few of the eggs are fertilized.
And there is always food and water inside and out, with most of the flock staying outside now that the weather is a bit nicer, so she has access to nourishment.
And once they hatch, they are in a nest that is a couple feet off the ground... should I put together a little floor nest for her? I have a milk crate that could suffice.
She has only been on them a few days, so if I move her I don't think she will complain too much...
All and any advice is so very welcome!!
Thanks!
Stephanie