I agree. You should seperate her. That just happened to me. Mine would leave her nest to take her potty break and another hen would then take her nest (usually lay an egg in there, which I would have to take out) and then my broody would get confused I think and find the nest closest egg to sit on. I caught this happen a couple of times and moved her back to the correct nest. Finally, I moved her nest so that she was secluded from the others. She was happy and so far has hatched out two chicks.