Every so often, I crack an egg open and there may be one or two "specks" or there may be a dozen or so floating in the white part. They look like dirt specks, but how does dirt get through the shell? It is unappetizing looking and I usually throw it away if there are more than one or two specks. I'm starting to sell my eggs now, and don't want to give these eggs to anyone. Any ideas on what this is?