Robin, I think it's just a myth to keep people behind in the game. I've bred females at 18-20 months with great results. I think size is the important factor when breeding. I've had plenty of females breed at 20-30 months old and have clutch sizes grow year after year. Just have to keep them feeding and feed them as much as they'll eat when they do.
Hi, how heavy is your female at 18-20 month old and at 20-30 month old? And their clutch size? TIA.