Orphan egg, how many days until it hatches??

[Maqui25]

Hi! 2 days ago one of our hens left the nest with 3 hatched chickens and left a bunch of eggs behind, this is the only one that seems to be alive. There is a possibility that it's not hers too so I have no idea how old the egg is. How old do you think it is? and how many days left would you say until it hatches? I had to improvise an incubator with a heating mat and the temperature is very unstable. I'm carrying it in my bra half the time bc of it

https://imgur.com/a/buaT8ba

 

[Maqui25]

Help please still seeing movement but no sounds, do you think it will make it?

 

[nuthatched]

Can you try to add heat sinks in the incubator? Your bra is not a good place for a delicate, porus egg.

 

[Maqui25]

Can you try to add heat sinks in the incubator? Your bra is not a good place for a delicate, porus egg.

Not right now but I'm planing on building a proper incubator in case it happens again, so that's very helpful! But I do have layers of clothes between the egg box and the mat, I'm monitoring every couple hours and I add or remove accordingly, I kinda got the hang of it by now