If she is actually sitting/broody (staying on the nest all day/night), she should not be laying any more eggs, at least not more than maybe one or two at the beginning... however other hens will lay eggs in her nest. If you do not have her separated from the other hens you will want to mark her eggs and remove any new ones the other hens lay each day. I personally would throw away any infertile eggs she has been sitting on since they have been "cooking" at 100*+ for a couple of weeks, too big of a chance for bacteria to be growing.
