well, my situation is probably a lot different than most people with ducks. My ducks spend a lot of their time inside in my sunroom/patio. They go outside in my very small yard each day, but it's only for a few hours until they get bored and demand to come back in. Because i live in a townhome that's in an urban area (right next to a fairly busy street) my ducks sleep in a special pen during the night in my art studio. (They have three pens, one in the sunroom/patio and two in my studio including a small one for sleeping and a bigger one for when i am not home.) So I collect their eggs from the sleep pen each morning. And i only got one egg each day for about a week....
Update: After almost a whole week of only one egg a day, i did find two this morning... both of which seem kinda big... maybe it just took her awhile to form that egg. lol... they are both still eating and pooping normal...