DESPERATE for an answer

I have a one year old production red hen who has gone broody. The papa is an Australorp, but I digress.

Unlike many folks I actually WANT her to be broody. Chicks get expensive when you are replacing each year. So, I 'm grateful to have her. However...

We have a smaller coop inside the barn coop (long story) but the laying boxes are in the smaller coop. We have 35 hens and 6 boxes to serve them. They use all but 2 of them and for whatever reason they won't lay in those two boxes. My problem is that Ms Broody keeps moving from nest to nest. SHe spends a couple days in one nest, go out to find her in a different one.

How do I keep this crazy girl in one box, staying on one clutch, so I can have some strange new type birds?

Thanks in advance