It's probably the shorter days. (Less hours of sunlight per day in the winter.) Temps don't seem to affect them as much as the light. If you want to trick them, you can gradually add artificial light with a timer to lengthen their days. If you're not in a rush, they'll probably start laying end of Feb or beginning March.Sebrights no eggs yet, 6 of my 20 hens started laying, the sebrights nothing yet. Not sure on their exact age but when i bought them the breeder said "should see eggs in a few weeks". The rooster is doing his job but not seeing any eggs. Also their combs dont appear to be full yet. Im thinking bc its winter? Even though im in the south & winters is 50 degrees average.
Depending on the season when they reach maturity, pullets can take 4-5 months up to 9 months to lay their 1st egg. The good news is that your pullets will have a strong start and long laying period in 2020.