And you’re welcome! Hopefully the little duck makes it but it seems fine so far! The hole you made won’t be an issue and now the duckling will most likely just resume normal hatching
Just wondering but what do you mean they breath through the membrane? From what I’ve seen and heard they break a hole in the membrane so they can breath the air cell and then once they externally pip, breath through the hole. I’ve seen many people use Vaseline and it is a pretty common practice...
So in my experience this isn’t really a big problem. Basically the reason you might not want to make the hole very big is because the egg will loose some moisture a bit faster than it should, causing the membrane to become a little tougher to break out due to loosing more moisture than usual...