Cluck cluck icemaiden and flock

do you have any idea what kind of ailment might cause the eggs to become smaller?
My celadon quail lay eggs about 10% smaller than other quail, i’m wondering if they have autoimmune problems because they seem to have the characteristic vit d deficiency that goes with it.
They’re generally more susceptible to everything though so it could be anything that causes the smaller eggs.
The more i research the more it looks like they were tinkered with in a Canadian university, I’m strongly apposed to this sot of thing but i love them now so keep them anyway.