Mystery Egg, Came In A Barnyard Mix For Hatching! (Duck, or Chicken Egg?)

[MysteryChicken]

Too rotten to open up and see if chicken or duck?
I open mine outside with egg inside a ziplock bag for stink factor.

I cracked it open, there was nothing inside, I caught it early enough so it didn't stink too bad.

 

[MysteryChicken]

The egg was only in the incubator for 6 days.