My 4 Welsh Harlequin girls were all laying an egg a day in one nest for the last few months. Suddenly we started getting 3 eggs one day, 2 another then 4 again for a couple days. The girls all look and act fine so I assume it's due to winter coming. The last two days we got 2 normal sized eggs and a marble sized egg, all laid in different places. Today we simply got two eggs. Everyone is looking and acting fine. The shells are normal on all eggs even the little ones. Can I assume this is due to the shorter days?