Duck egg help

[Lucyface]

My neighbour found an abandoned duck egg and gave it to me.
I made a makeshift incubator and have been candling it.
Could anyone offer advice as to whether it's alive and how old it might be?
I will add some pictures, they aren't the best but there are obvious veins under the air sac and the rest of the egg is black so I assume there's something in there.
There is some discolouration on it which worries me.
There's no smell and no movement. I've had the egg for about 3 days now
Any and all help appreciated. Thank you!

 

[SilverBirds]

Welcome to BYC!

Pictures are very helpful.

Duck eggs normally take 28 days to hatch, depending on breed. Temperature should be at 99F, humidity should be kept around the 50s. If it was found, the egg most likely belongs to a mallard.

 

[cheezenkwackers]

Welcome! I’m sorry to say that your egg is not alive. I would dispose of asap.

 

[Lucyface]

Welcome! I’m sorry to say that your egg is not alive. I would dispose of asap.

Thanks for your reply. How can you tell?

 

[SilverBirds]

It looks like he was close to pipping date, but got shrink wrapped. You can open the top of the egg if you'd like.

 

[cheezenkwackers]

Thanks for your reply. How can you tell?

Sorry, but I have lost several over the years. Lack of blood vessels, that light fluid on top, no movement, no internal pip, all bad signs. You can keep waiting or as SilverBirds suggested, you can make a small hole into the side of the airsac end and look. If I am wrong, the baby can still hatch.