I live in Vermont at a high-ish elevation. Last spring, my two Muscovy hens started laying for the first time at the very end of March and the beginning of April. They were just about ten months old at that time. My Rouen started some time in late April, but she has major issues laying and is a bit older. The year before, she started at the end of March. I do not use artificial light. Last year was far more brutal than this winter has been (so far). I know that the amount of daylight is most important, but I’ll be interested to see if they will lay sooner due to the milder (so far) winter. As far as conditions go, there was still snow on the ground last year when they started laying, and it was still pretty darn cold.