Bullseye on yolk = fertilized egg?

[kesrchicky16]

By the way, since I'm not sure if you meant you thought your hen was crazy because she went broody with no rooster, they definitely don't have to have mated or have fertile eggs to go broody. When their hormones tell them to do it, they do it, whether they have ever seen a male in their lives or not

AMEN!
When I got my roos I swear my broody butt buff Orpington said "I've had sex and so have my friends. You're not tossing me off these eggs." She hatched out 2 of 6. I had 1 RIR bite me over the imaginary eggs she was sitting on. Those are the times I tell the birds they are nuts. If there are not eggs under you, you are a mentally ill chicken. Come spring they will have a chick proof coop and run and broodyness will be treated with a nestfull instead of flight lessons.