We haven't cracked it open yet so I don't know how many yolks. The hen that laid it is a Rhode Island Red that just finished a mini molt.
I am not sure how you would "encourage" a hen to lay big eggs but I certainly have done nothing differently. She laid a normal egg today.
So Saturday my daughter comes in from checking for eggs and says "Mom, you have got to see this egg!" I just thought I would share it with some people here who would also appreciate it. I also took pictures on my blackberry and posted them on Facebook and showed them to friends and family...