Selection of true “Jumbo” Japanese quail (Coturnix japonica)

A little everywhere in Belgium and abroad I saw appear advertisements and/or publications of breeders claiming to have “Jumbo” Japanese quails (Coturnix japonica)
Hear here: large birds, selected for the production of flesh.
In Germany, these animals are also called “Mastwachteln”.

However, the term “Jumbo” is misused, because many breeders have no idea of the maximum weight those quails can reach and believe they have large birds because they have never seen anything else …
There are also breeders who have birds of very large size and they do not call them “jumbo” so far.

In my opinion, the “Jumbo” Japanese quail should be defined on the basis of an indisputable criterion: their weight.
For this reason, I decided to define the “Jumbo”  like this :

Adult breeding females of the Japanese quail (Coturnix japonica) with a minimum weight of 450 grams and producing female juveniles reaching this weight after 6 weeks of life.

My breeding females are weighed and their eggs are also selected on the basis of their weight. For the incubation, I use only eggs with a minimum weight of 15 grams.

See below a few pictures clearly showing the difference in size between eggs of ordinary Japanese quail and those from real “Jumbo” birds.