Most all hems will lay eggs that are the same color, size and shape, day after day. Over a period of months the eggs will usually get a little bigger. For most of my hens I can tell which hen laid it by its shape. Certain ones put out a long skinny egg, some real pointy, and one of mine puts out a nearly perfect round egg. I seriously doubt that any of your chickens are putting out 2 eggs per day. If and when that happens is usually because they were young and may have laid one at sunrise and a rubber egg at sunset. Most breeds all require a minimum of 25 hours from the time one egg is laid till theY can make and lay another. You are a million times more likely to have a hen take a day of from laying than to have it lay twice in 1 day. Everyday a hen will lay about an hour to two hours later than the previous day. Mon egg @ 8am, Tues egg@9am and so on. Once she is due to lay about dark thirty she will hold it in till the following day so you won't get an egg that day. Next day she will start laying again at sun up. It's just how laying eggs works. some young pullets are known for doing 2 ovum/yolks in one day, but they almost always end up in the same she'll, double yolkers. Even if a chicken managed to lay 2 in one day, it certainly would not happen again for a long time and it would never ever happen every single day. I'm not calling any one a liar. But if you honestly think you're getting multiple eggs per day from one bird, you better isolate that bird, instigate to make sure someone isn't pranking you, if it is true, call the World Book of Records, then get ready to sell that bird for millions. Because if that bird does lay daily multiples every egg producer in the world will want to study it and use it for being stock.
Here's an article on BYC that gives you the God's Honest Truth all about eggs.
https://www.backyardchickens.com/articles/interesting-facts-about-chicken-eggs.63122/
Here's an article on BYC that gives you the God's Honest Truth all about eggs.
https://www.backyardchickens.com/articles/interesting-facts-about-chicken-eggs.63122/