Late duck eggs?

[Juby26]

Hey I have 6 Campbell duck eggs that I started incubating on the 15th August, which should bring their hatching day to 12th September (I think!), I've been candling them along the way and the air sacs have been getting bigger so in pretty sure there is something in there, I went into lockdown on Wednesday, and I haven't touched them since and have increased the humidity. I haven't heard anything from them at all! I'm just wondering, is it normal for them to take this long? Should I do something?

 

[Juby26]

Should I do the float test?

 

[Juby26]

Help!!

 

[needlessjunk]

Let me tag some people that may be able to help @Lacrystol @caesargirl @City farm @jtn42248

 

[Juby26]

I opened them all up and there wasn't anything in any of them (

 

[momie8x]

maybe they were not fertile to begin with.