Tbh you likely have more raccoons than you realize. They thrive in neighborhoods where they can steal cat food off a back porch and pillage a dumpster. Also they will act out of character greatly expanding the areas they search for food when winter comes. Foxes as well. Almost every fox I have...
Imo peal the egg very carefully towards the dark spot. That looks like an internal pip to me. If it's not simply make a small hole and leave it a little longer. Ducks do take longer to hatch and that can be nerve wracking.
(1) Are you new to chickens / when did you first get chickens?
My mom got chickens 16 years ago after immigrating our family to Australia. They were silkie chickens. I got my first chickens myself in my early 20s but suffered a terrible miscarriage that almost killed me so I gave them to my mom...