When I had a bunch of chickens, I could count on almost one egg a day from each.
But; if you have DUCKS; they also are as prolific, but the eggs are TWICE the size (and they taste just the same) as the chicken ones. (and are tinted green!)
https://www.google.com/search?q=worldwide+chicken+or+duck+eggs&ie=&oe=
Chickens lay 80% — 8 eggs per 10 chickens per day.