Soft eggs in young quail - with pictures

[Huntmaster]

A pic of different size of my eggs from largest too small in size for reference. I have some birds that always lay the larger eggs and others that just lay the avg.

 

[Linita]

A pic of different size of my eggs from largest too small in size for reference. I have some birds that always lay the larger eggs and others that just lay the avg. View attachment 3407886

I don't really get the size with the coin, since I don't really know american currency, but from the weights a bit.

I have two quails
How much do jumbo quail weight? Mine are 230g and 260g, they're Isabelle. I think Isabelle are a bit bigger than average but not as big as jumbos.

I am actually a bit confused about quail spieces/colors. Also here in Spain people use different terms.

Some people write that japanese coturnix quail can come in different sizes and colors, but it's all japanese quail. This is what makes sense to me.

Other people say they're different types of quail depending on the color. For example some people call isabelle only to the golden quails, whilst other people say isabelle is just about the size and other properties, and that they come in all colors.

Also confused about Button Quails, here they're called chinese quail. And I see other people refer to them as king quail. But apparently, not the same as buttonquail? which is what came up in google when I looked it up.

Do people get chinese quail for some farming purposes? or is it just a decorative/pet purpose? I don't understand why people would keep them if they're so small for farming purposes.