I have 2 female ducks. They have always layed an egg each a day since I got them in August. Then it went down to just one egg a day, and from the same one. Now it has been 3 weeks going on 4 since I have had any eggs from them at all. They are a year old so it can't be age? do they stop laying in the colder weather? I loved my duck eggs and want them to start laying again.