Day 32 for my Rouen eggs

[lowe34]

I need advice, I had 10 eggs under my broody duck she went broody on the evening of March 31st. So this evening it will be 32 days. I lost 3 that went rotten, and then last week had one go rotten, but had a feathered duckling in it, and then when I candled today there was no movement in one so I opened the air sack portion of the egg and still nothing, still lots of blood vessels and a good bit of yolk. The 5 eggs remaining look good, but 2 of them have huge air sacs that take up about half the egg, but none of them have an internal pip. I don't want to lose any more ducklings, I don't know if I should start preparing to assist, or if I should just continue to be patient?

This is the first one that was about 17 days or so

This is the one I checked on today with no movement