Cayuga Egg Incubating

[Pollopato]

Hello,
I just did a run of khaki campbell/magpie duck eggs and some cayuga duck eggs in my incubator. Almost all my khaki cross eggs hatched on their own but none of the cayugas hatched at all. Three got their bills out but then died within a day. All but a couple were almost fully developed. Do cayugas have a thicker shell? The only difference was i bought the cayugas from someone else and they were dirty compared to my khaki cross eggs. Should i have increased the humidity? I did 60% humidity until the last three days and then i increased to 70%. Thank you for any ideas, advice you may have.
Cheers.

 

[Yardmom]

60 is quite high for a before lockdown humidity. How were your air sacks? If they were small you want to lower your humidity before lockdown.

 

[Corbdee]

60 is quite high for a before lockdown humidity. How were your air sacks? If they were small you want to lower your humidity before lockdown.

X2. Also sometimes new Cayuga layers lay dark gray or even black eggs, and that black outer layer on the egg I see actually another shell type substance over the actual egg, which sometimes makes the eggs thicker. But it could have been a combination of everything you mentioned

 

[Pollopato]

60 is quite high for a before lockdown humidity. How were your air sacks? If they were small you want to lower your humidity before lockdown.

The air sacks were pretty large. A 1/3 of the egg size i suppose. Maybe a tiny bit smaller than 1/3. Is that too big or small?