This happened on day 18 of their 35 day brooding and overnight it was 65 degrees F. I read that with incubators they may still hatch so I continued to have the duck sit on them and only one did not hatch. And I didn't let my husband put them in at night because that's how she got locked out that...
My pen for the Mom and ducklings is 4 feet by 12 feet and today another Mom with 5 ducklings now needs a mongoose proof place for herself and her ducklings. Had planned another place for her but thought I had 2 more days to hatching. If you have experience with this please tell me.