David,
I’d suggest that the Japanese Quail is the only one that breeds easily enough to be the likely suspect for this question. It is almost, if not fully, domesticated (not indigenous) and tends to lay eggs all over the place. The quail I have seen in supermarkets are clearly at a quick look much too big to be King Quails. Although the King Quail also breeds fairly easily in good aviaries, they are small and surely not productive enough to be commercial useful. They produce far more males than females and this is not good for continuous production.
Philip
