No, that monster egg was not layed by Lady Sandstorm. She layed the little egg next to it.
If I'm right, the eggs have been in the incubator for four days! Maybe I'm wrong. Please hatch, eggs.
I was planning on setting all five eggs but Lady Sandstorm layed another that day so hopefully there will be six Serama chicks! Probably we'll only hatch one. And it will be a rooster. Oh, well. In one of those Magic Treehouse books Jack learned "If you don't succeed at first, try, try again". I can do that.