Anything they do involving first eggs I've learned is somewhat normal! One of my girls laid two eggs her first day (we had a tiny egg binding scare so she was a bit backed up). As for it being the size of a chicken egg, that is pretty normal as well. I was a bit sad because I thought my breeds were meant to lay larger eggs. They have been laying for a few weeks now and the eggs are measurably larger than the first few they laid. Both of ours lay very pretty green eggs, but someone decided to lay a white one yesterday, completely confusing me and making me think they had a wild duck over for a slumber party, haha. Congratulations, by the way! It's very exciting, isn't it?! Even though my ducks aren't big on the whole '1 place to nest' concept, and every morning before work I have to wake up early and go on Easter egg hunts, I still am so glad we decided to raise ducks.