Our newest batch khaki campbells have started laying about 2 weeks ago and some of the eggs have green yolks. There is no unusual smell to them, but they look quite strange. Are these safe to eat or do we need to address this issue? They are free range with many acres available to them, lots of bugs and seeds, etc with a well balanced feed in the am and pm. We've been raising ducks for 3 years now but this is a first. Any clue? Thank you!