Broody hen whose eggs have been eaten

[Anonymous]

I have a broody hen who has been sitting on eggs for one week. Last night a rat knawed through the box she was in and ate the eggs from underneath her.(She is in a wooden box inside a metal dog cage).
If I sit her on more eggs, will she sit still for another 3 weeks or will she sit for another 2 weeks and then get up. Does anyone know ??
By the way, I will make the mesh smaller too !!