Make sure you take a picture like this to show the difference in fertile and infertile eggs.
I found that here http://www.gabbardhatchingeggs.com/blog/fertile-vs-infertile-eggs/9/2/2011
I need to show that to my Mom next time I'm down there. I've had a hard time explaining it to her. She used to think the blood spots were from it being fertile.
Good idea! Thank you!