Duck eggs

Hi! I have tried to make cake using duck eggs. Both times the cake didn't rise and ended up flat, like a brownie. Is it because of the duck eggs? Do they have a different protein than hen eggs or something like that? More info: both times I just replaced the hen eggs with duck eggs. Followed measures and instructions from the recipe and didn't change other ingredient. I have made very nice and fluffy cakes before. These tasted good, but the texture was dissaponting. Thank you!! submitted by /u/procatthief