That's what has been happening in my hen house.
Thought my Marans was over her broodiness but she's back
on the nest and she has a Buff friend with her. Eggs are being broken
cause everyone wants the same nest.
I would recommend you move your for-sure broody to her own crate/pen so the broken eggs thing stops. She will most probably put up a squawk being moved, but you need to especially if you want her to set eggs and hatch them.