How old is this egg/is it viable ?

[montpa01]

Hi. We rescued these eggs and have been trying to incubate them the past week using a makeshift incubator (plant propagator with humidity/hydrometer and hot water bottles) we've kept them between 30-40 degrees and as it's hard to maintain constant temperature with hot water bottles. keeping it around 50% humidity
This is the only one I believe to possibly be alive (others have no veins) and it's looked like this about a week now the only difference is the veins have got a bit fainter. (There was another one with veins but the veins have gone so I'm assuming it's probably died but I'm still keeping it incubated just in case)

There's absolutely no movement inside and there seems to be fluid/bits floating slightly inside. I have no clue what I'm doing really and need a trained eye to take a look. I've googled it and I'm guessing it's fairly late into development.

Thank you very much !

 

[Ratchnick]

How long have you been incubating it? 10 degrees c is s huge temp swing.

 

[montpa01]

How long have you been incubating it? 10 degrees c is s huge temp swing.

a few days in the propagator. before that they were in blankets with water bottle.
i know its a huge swing, i've been trying to keep it constant but it's been difficult to

 

[aart]

We rescued these eggs

Where did you 'rescue' them from?

 

[montpa01]

Where did you 'rescue' them from?

nest was behind my mums work. no sign of mother duck for over 24 hours and found her dead nearby.