Probably not Hygienic behavior there (although maybe). Even un-hygienic queens will miss a cell every now and then. If there are a few hundred on a frame (I don't know, never counted them), the queen is bound to miss at least one of them. Or maybe when she was laying there, the cell wasn't cleaned out or something.So does this all mean that when I see an occational empty cell in an otherwise solid frame of sealed brood, it is a good thing? I have seen frames with a solid rectangle of sealed brood except may be a dozen random empty cells, I was just glad to see the solid rectangle and added another deep.