Hello, and thank you in advance. I started incubating on 3/27 at 11p. 3/28 was Day One. Today is Day Thirty-Five. I candled on Day Eight and 4 eggs were non-fertile. Candled on Day 16 and all ducks were growing and moving. Only 11 ducks hatched. Two died. One was clicking when he was breathing and was breathing heavy and laboured. He died the first night. After I realised this duck was sick, I gave all the ducklings 2 cups of Duramycin-10. Another died the second night. No previous signs of illness. 1 pipped 4 days ago and has not moved since. Incubator has been at 55% relative humidity and 99-100F until lockdown. During lockdown humidity was 70-75% and temp. was at 98F. We did open the incubator during lockdown to replenish water source and move ducklings from the top shelf. Any ideas why 22 of my ducks did not hatch?