I have been down this road before, (hatching 25+ years). I know doubles usually only make it to day 10 or so. I do find this egg interesting.
(This EE egg below is not the egg but an example of a fertile egg one day in.) The egg below is not a double but you can see what I call a "love dot" when an fertile egg has been in an incubator for one day, you get a shadow the size of a pencil eraser. If you roll the egg gently in the light, it races around in the egg.
View attachment 3383920
The one day incubated egg below has 2 Love dots. When candled yesterday the dots were closer together, now they have spread a bit. This is not a big egg it is a golden Spitzenhauben egg. She is young.
View attachment 3383922
I will post more pics as I go if anyone wants to follow along. (My page is judgement free. But you are welcome to make polite comments. Thank you.)
(This EE egg below is not the egg but an example of a fertile egg one day in.) The egg below is not a double but you can see what I call a "love dot" when an fertile egg has been in an incubator for one day, you get a shadow the size of a pencil eraser. If you roll the egg gently in the light, it races around in the egg.
View attachment 3383920
The one day incubated egg below has 2 Love dots. When candled yesterday the dots were closer together, now they have spread a bit. This is not a big egg it is a golden Spitzenhauben egg. She is young.
View attachment 3383922
I will post more pics as I go if anyone wants to follow along. (My page is judgement free. But you are welcome to make polite comments. Thank you.)