Membrane after pipping changed colour…normal?

[Seeni133]

Hello

I have two duck eggs. Both internally pipped yesterday morning. One externally pipped himself about 1pm. The other we made a small air hole for. I’ve checked them both tonight. No progress, as expected. The air hole fella is a bit less chirpy. The external pipped fellas membrane where he knocked off some shell is a slightly off colour. No longer bright white, but heading towards brownish. Is this normal?

 

[citymeetscountry]

Mine that pipped away from the air cell turns a color but the others seemed to stay white from what I could tell. Can you tell if it actually penetrated through the outer membrane?

 

[Seeni133]

Mine that pipped away from the air cell turns a color but the others seemed to stay white from what I could tell. Can you tell if it actually penetrated through the outer membrane?

Both are chirping away. Else I don’t know, if they are in the air pocket. It looks as if the membrane is intact, just the shell has been pushed off but the wee fella. It’s day 31 now. Utter novice here. Well read but first hatch. They are khaki/runner/Aylesbury.