After candling a clutch of eggs our mallard has been sitting on for approx 10+ days, we believed they were not fertile. Before discarding them, we decided to break one open to find we were wrong (first year raisers). We put the eggs back in her nest & she did go back & sat on them after we left. We didn’t think she was going to & went & bought an incubator, but came back to find she is. Can anyone tell us about how far along in the hatching process this duckling was?