Hatching Double Yolk Eggs!!!???

[bonsaiherb]

How do you candle brown or blue eggs? Have a mini-incubator and am trying but I fear some of my pullet/hen Ameraucanas will be double yolkers. If so, I would be LUCKY to expect even one twin to survive.

 

[FoxyDragon]

What day of incubation do twins hatch? Is it early like in other animals?