does broody hen know the answer?

I have an experienced little bantam,  who went broody last week, so I purchased on ebay 6 lavender pekin bantam eggs for her, they arrived intact, so I took hem out to her, removed the china eggs, gave her a drink food and she had a dust bath and back to the nest to find her new eggs.
She pulled them all in under her and sat tight as usual...she is such a good mum....Went out this morning to let the chooks out and she rushed out too....quite shocked, 
looked in to find only one egg in the nest and the rest rejected.....question is does she know at this early stage they are not fertile?
I put all the eggs back in the nest and she had a drink and came back in and sat on them all again.....will she reject them again if they are not fertile or has somthing put her off, she is normally bomb proff and nothing has put her of before

boodys are a sitting target for lice and mites.
as she had a dust bath she could be bothered by them, perhaps redo the nest box give it a good clean out spray etc fresh bedding and give her drops like frontline to help her.
hopefully this should settle her down and put the eggs back under her.