I forgot to mark the calendar when she started to go broody, been on and off the eggs because the other hens kept laying in her nest and she would go sit on another bunch of eggs. I think it has been more then 21 days, I tried candling the eggs and they are very dark, so I will wait a few more days, MY QUESTION IS!! if I put fresh eggs under her will she sit another 21 days till they hatch?... or should I just wait till she gives up?