I have 2 Cayuga Ducks about 7-9 months old. Im almost positive they are females because they do not have the curled drake feather. we have gotten no eggs from them at all. they are housed with my chickens and all get along fine. plenty of food, water and treats for all. they have their own area in the coop where the hunker down at night. any ideas why they haven't laid? any thoughts would be aprreciated?