why do some eggs have freckle-like spots on the shell?

Question

the title sums it up pretty much, thanks :\]

In: Biology

Answer 1

Birds don’t have teeth as we do so they eat sand and grit and use a rubbing motion in their “throats” to break up their food and sand and grit make that process easier, then some of that goes through their digestive system and lands up as a mineral deposit in the egg shell