18 month old female pewter at 1400+/- grams and she produced 5 large eggs.
18 month old Pastel at 1300+/- grams and produced 4 eggs.
5 year old pastel at 2400 grams and produced 4 eggs.
7 year old het pied at 5500+/- grams and produced 14 eggs.

I don't think age matters as much as weight. Females are probably fertile at 800 grams believe it or not. I'm not saying it's healthy to breed them at this weight, but I do think it's possible. BTW, I voted over 1200 grams.