who layed the eggs???? duck or chickens?

ok, my eggs are oddly shapped. Can anyone enlighten me on what is happening with our egg shapes? We thought it was a duck egg, then thought it was from a hen because one was outside of the coop where my NHR hens get out but the duck was in the coop the whole time. Now my hubby thinks that they are duck eggs again. they are more oval shaped. They are similar to a football shape. They are off white in color but there is no large rounded end as both ends are equal. Do chickens have eggs llike that too?