In 920 AD, the selection for a thyroid-stimulating hormone receptor variant in European chickens enabled year-round egg production. This genetic advancement marked a significant milestone in poultry breeding, allowing farmers to increase egg output and improve food supply consistency. The ability to produce eggs throughout the year transformed agricultural practices and contributed to the development of the poultry industry. This innovation played a crucial role in meeting the dietary needs of growing populations in Europe.

The TSHR gene variant enabling year-round laying around 920 contributed to a reliable food supply, inspiring medieval ballads and folk poems. These works celebrated seasonal abundance and the agrarian lifestyle, reflecting the interconnectedness of nature and human existence.