I have 2 Muscovy ducks and 11 hens . The ducks are about 7-8 mos old. I get about 6-7 eggs a day. For the past couple of weeks I get about 1 egg a day that is slightly larger with a slightly thicker shell. When I crack it, the white is thicker and tends to kind of stick to the shell a little. What do you think?? Sound like a duck egg?.