Question about Yolk to White Ratio

[so lucky]

I know there are a lot of very knowledgeable chicken folks on here, so I wanted to pose this question:
What is it that makes chickens lay eggs with huge yolks and sparse whites, versus others that lay huge eggs with lots of white and smallish yolks?
One might think this is an optical illusion, but when I crack eggs in a bowl, some from my chickens and some from a chicken farm, the difference in yolk size is very noticeable.
The eggs from my chickens, by the way, are the large yolked ones, which is fine by me, because I like the yolk more than the white. I just wonder what makes the difference.

 

[Smart Red]

Waiting for someone else to offer a suggestion.

 

[so lucky]

Oh, and did I mention that my chickens' eggs taste much better than the "farm fresh eggs"?

 

[Nyboy]

Are your chickens laying double yolks ?

 

[journey11]

I've noticed that too. My egg yolks are huge compared to store bought eggs. I don't know if it is genetic on the part of the chicken or maybe it's just all of the good treats and forage they get. Color of the yolk is definitely affected by foraging for greens. Well, and those production hens lay a greater number of eggs in a year. Perhaps a less productive layer makes bigger yolks since the egg travels the oviduct a bit slower?

 

[Nyboy]

ask @Beekissed she had some battery hens in her flock.

 

[so lucky]

No double yolks, Nyboy. I think I've only had maybe 3 in the 4 years of chickens. Maybe diet has more to do with it than genetics since my chickens are 4 different breeds. Interesting idea of the slower egg passage allowing for larger yolks.
@Beekissed, what do you think?

 

[Beekissed]

I think it's diet and seasonal whether the yolks are giant or not. But then, I've noticed some chickens always have a larger yolk than others no matter what the season and on the same diet as others, so it can also be genetic.

When I switched to fermented feed I started noticing even larger yolks than normal and mine are pretty large anyway. Then, later on, that settled down and the yolks went back to their normally large size but were no longer super sized.

But always...always...my chickens have larger yolks than store eggs. I think diet more than anything.

 

[seedcorn]

White vs yolk is based on genetics.

Bantam eggs have yolks about same size as standards but much less white.

Commercial hens are selected for feed efficiency, laying %, and consistent size of egg (large). The % of white to yolk is of no matter economically.

 

[Beekissed]

I disagree with that. Though I've seen certain birds within the same breed having a consistent larger yolk than her flock mates, which would suggest a certain genetic component, I've noticed that the yolk size can vary with the season, with the change in forage and feeds and also with the level of hydration of the bird. I've kept many different breeds within the same flock, through many flocks down through the years and notice more consistency of yolk size throughout the flock as opposed to breed from breed.

 

[so lucky]

It just doesn't make sense to me that the little Sussex lay small eggs that are almost all yolk, and some humongous eggs we got from a production farm, albeit a "free range" set up were over twice as large of eggs, but had smaller yokes. Then our normal size eggs have larger yokes, too.
If they were to be fertile, which determines the size of the chick, the white or the yolk?