I find it hard to believe a mixed rooster would throw a good laced pattern like that, even if the mother was pure. that's like a 0.1% chance... I would say isolate her to be sure before judging... she could have just been checking out the nest but not laid yet, or had already laid elsewhere.
Oh yeah, and I called the breeder and he admitted he had another blue laced red wyandotte that was throwing olive eggs, he thought it was so cool. I won't be using him as a source any more, there is no way he should be calling them wyandottes if it is producing olive eggs. I'm really happy I have a olive egg, but I certainly shouldn't be getting it from my wyandotte.She laid the egg right in from of me. I know for sure it was her!