Problem incubating duck eggs

[CJG4]

About 3 months ago i tried hatching 120 duck eggs in 3 different tabletop incubators. Each time i candled the eggs and a good majority of the duckling were alive and well all the way up until the hatch date. Every set of 40 eggs would have 25 to 30 alive by the hatch date. But then on the hatch day, all of them seemed to weak to get out of the eggs. They would make one pip hole and then seem to give up. I started helping some out after i saw the pip hole but that rarely helped. They were still too weak. I only ended up with 11 ducklings. The temperature was 99 to 100 the whole time and the humidity was 55% in the first 25 days and 65% in the last 3 days. What could be the cause of them being so weak and not being able to make it out of the egg?

 

[mnferalkitty]

There not weak that is how ducks hatch. Helping them can be a problem for them, they have to struggle out of the egg to get strong.
One thing that threw me for loop when I first started hatching duck eggs is they pip then make a hole in egg and work on that hole to zip and sometimes it can take 2-3 days!!

 

[CJG4]

When yours took 2 to 3 days to get out, were they fine after that? I tried letting them go by themselves and some would make it out but most would die in the egg with just one pip hole.