Peking eggs, day 20, what should I see?

[2 many chickens]

My Pekin ducks are now day 20 in my incubator. I candle a while ago and couldn't see much. Some have air sacKS at the top, all black. Some can't see in it at all. One looks like a big air sack. Air sack looks like it moves around? Some orange and black. Doesn't look like the others. BUT it doesn't stink. I had to toss one out 2 weeks ago because it smelt so bad. This is my first time doing this. Don't want to toss what could be a healthy egg.. don't want to have one explode and blast the other eggs to space. Should I just leave them alone? Can the healthy eggs hatch IF there is a deaD one in there?

Thanks all :/

 

[2 many chickens]

Also, the one with the big air sack doesn't look like it's moving. black thing (I'm assuming that's the duck) looks smaller than in other eggs.
Basically what should I be seeing that's normal on day 20. I'm a newb at this lol

 

[2 many chickens]

Quack.. any advice????

 

[Eagle Flight Farm]

See the duck egg candling chart of pictures at this link:

http://wildliferehabber.com/candling-eggs