I'm pretty sure either one or more of my ISA brown pullets that just started laying in February is laying double yolks at a crazy pace. I've had 4 double yolkers in the last 2 weeks. They are huge! I feel bad for the chicken pushing those out, but it made me wonder - how common are double yolked eggs? Are ISA browns (bred for egg laying) more likely to lay a double yolked egg than other breeds?