Here's my .02 on egg color and photography.
I am a printer by trade. My job is to make the solid images ( on paper, canvas, plastic etc.) from digital images of pictures and artwork and visa versa. This is my trade. I have been doing it for 40+ years and I am good at it.
From this perspective, I must say:
I have, at my business,many computers but 4 different monitors. Blue shades look different on each one. Each computer will throw it's own blues and each monitor does so more accutely. I regularly have to adjust my equipment.
TK Poultry has the ONLY true way of dealing with color.
The eggs need to be photographed with a scale attatched to the photo taken simultaniously with the subject.
If we all had an egg color chart, that would also work, as each egg picture can be identified by the color chart's letter & number.
Barring that, the chart needs to be part of the picture.
That's the way it works in my field. I'm not a photographer. I'm not a lot of things. But on this narrow subject, I am an expert.
Edited because typing is something I am NOT an expert at.