A broody hen

[doug]

Wonder if someone can help? I'm new to this site, and relatively new to keeping hens. I have three (all good layers). I got a cockerel for my girls 11 days ago and 4 days ago, the smallest one went broody. Problem is, whilst there are 4 boxes, they all three used to lay in the same one (with the lagest opening) before the cockerel arrived. That's where she is at the moment. So my questions are:-
Will the eggs be fertile?
How can I stop the others laying more in the box with the broody one (God knows how many she has under her now)?
How can I look and see? I can't get near her, she seems to be very aggressive and I don't know how she would react to being disturbed forcibly.
Her box has a smaller opening that the others cannot get into. If I moved her and the eggs to that one, would she continue to sit on them?
Best regards
Doug. (Living in the Dordogne)